Can't connect to esp8266 (ESPTOOL-941)

[radio-satellites]

Operating System

Windows/Fedora Linux

Esptool Version

esptool.py v4.8.1 4.8.1

Python Version

Python 3.12.6

Chip Description

ESP8266

Device Description

My own PCB. I've double checked all strapping pins, they seem fine.

Hardware Configuration

GPIO16 - SDN GPIO4 - NIRQ GPIO15 - NSEL GPIO14 - SCK GPIO13 - MOSI GPIO12 - MISO

All of these are connected to an Si4432.

How is Esptool Run

Terminal, arduino IDE

Full Esptool Command Line that Was Run

python esptool.py --chip esp8266 --port COM9 --trace --baud 78400 --before default_reset --after hard_reset write_flash 0x0 C:\Users\sasha\AppData\Local\Temp\arduino_build_160028/sketch_oct10a.ino.bin

Esptool Output

esptool.py v4.8.1
Serial port COM9
Connecting...TRACE +0.000 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.117 No serial data received.
.TRACE +0.091 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.125 No serial data received.
.TRACE +0.092 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.131 No serial data received.
.TRACE +0.100 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.100 No serial data received.
.TRACE +0.100 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.100 No serial data received.
.TRACE +0.748 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.015 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.102 No serial data received.
.TRACE +0.092 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.124 No serial data received.
.TRACE +0.092 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.131 No serial data received.
.TRACE +0.100 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.047 Read 1 bytes: 0d
TRACE +0.000 Read invalid data: 0d
TRACE +0.000 Remaining data in serial buffer:
    0a20657473204a61 6e20203820323031 | . ets Jan  8 201
    332c7273742063                    | 3,rst c
.TRACE +0.101 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.114 No serial data received.
.TRACE +0.247 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.016 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.108 No serial data received.
.TRACE +0.091 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.077 Read 1 bytes: 0d
TRACE +0.000 Read invalid data: 0d
TRACE +0.000 Remaining data in serial buffer: 0a20657473204a616e202038203230
.TRACE +0.103 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.113 No serial data received.
.TRACE +0.098 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.102 No serial data received.
.TRACE +0.091 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.125 No serial data received.
.TRACE +0.755 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.048 Read 1 bytes: 72
TRACE +0.000 Read invalid data: 72
TRACE +0.000 Remaining data in serial buffer: 662063616c2073656374
.TRACE +0.095 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.000 Read 205 bytes:
    6020a26a81623861 60796020a26a8162 | ` .j.b8a`y` .j.b
    20a26a81a2386238 a298a55e59616079 |  .j..8b8...^Ya`y
    60386160796020a2 6a81623861607960 | `8a`y` .j.b8a`y`
    20a26a816220a26a 81a298a55e596238 |  .j.b .j....^Yb8
    6160796020a26a81 6220a26a81a298a5 | a`y` .j.b .j....
    5e596220a26a81a2 98a55e59a298a516 | ^Yb .j....^Y....
    187a9068f1697099 2478f9ead92c8571 | .z.h.ip.$x...,.q
    28d1aa386238a298 a55e596160796038 | (..8b8...^Ya`y`8
    6160796020a26a81 62386160796020a2 | a`y` .j.b8a`y` .
    6a816220a26a81a2 6a7960386220a26a | j.b .j..jy`8b .j
    81a298a55e59a298 a55e596160796038 | ....^Y...^Ya`y`8
    a298a55e59616079 6038616079602062 | ...^Ya`y`8a`y` b
    386220a26a81a298 a55e59a298       | 8b .j....^Y..
TRACE +0.016 Read invalid data:
    6020a26a81623861 60796020a26a8162 | ` .j.b8a`y` .j.b
    20a26a81a2386238 a298a55e59616079 |  .j..8b8...^Ya`y
    60386160796020a2 6a81623861607960 | `8a`y` .j.b8a`y`
    20a26a816220a26a 81a298a55e596238 |  .j.b .j....^Yb8
    6160796020a26a81 6220a26a81a298a5 | a`y` .j.b .j....
    5e596220a26a81a2 98a55e59a298a516 | ^Yb .j....^Y....
    187a9068f1697099 2478f9ead92c8571 | .z.h.ip.$x...,.q
    28d1aa386238a298 a55e596160796038 | (..8b8...^Ya`y`8
    6160796020a26a81 62386160796020a2 | a`y` .j.b8a`y` .
    6a816220a26a81a2 6a7960386220a26a | j.b .j..jy`8b .j
    81a298a55e59a298 a55e596160796038 | ....^Y...^Ya`y`8
    a298a55e59616079 6038616079602062 | ...^Ya`y`8a`y` b
    386220a26a81a298 a55e59a298       | 8b .j....^Y..
TRACE +0.000 Remaining data in serial buffer:
    a55e596160796038 a298a55e59616079 | .^Ya`y`8...^Ya`y
    60386160796020a2 6a816238a298     | `8a`y` .j.b8..
.TRACE +0.094 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.000 Read 235 bytes:
    20a26a816220a26a 81a298a55e596220 |  .j.b .j....^Yb
    a26a81a298a55e59 a298a55e59616079 | .j....^Y...^Ya`y
    60386220a26a81a2 98a55e59a298a55e | `8b .j....^Y...^
    596160796038a298 a55e596160796038 | Ya`y`8...^Ya`y`8
    61607960206d72c7 6238623861607960 | a`y` mr.b8b8a`y`
    20a26a816220a26a 81a298a55e596220 |  .j.b .j....^Yb
    a26a81a298a55e59 a298a55e59616079 | .j....^Y...^Ya`y
    60386220a26a81a2 9836653861607960 | `8b .j...6e8a`y`
    20a26a8162386160 796020a26a816220 |  .j.b8a`y` .j.b
    a26a81a298a55e59 6238a298a55e5961 | .j....^Yb8...^Ya
    6079603861607960 20a26a8162386160 | `y`8a`y` .j.b8a`
    7960a26a816220a2 6a81a298a55e5962 | y`.j.b .j....^Yb
    386160796020a26a 816220a26a81a298 | 8a`y` .j.b .j...
    a55e596220a26a81 a298a55e59a298a5 | .^Yb .j....^Y...
    5e59613862386220 a26a81           | ^Ya8b8b .j.
TRACE +0.016 Read invalid data:
    20a26a816220a26a 81a298a55e596220 |  .j.b .j....^Yb
    a26a81a298a55e59 a298a55e59616079 | .j....^Y...^Ya`y
    60386220a26a81a2 98a55e59a298a55e | `8b .j....^Y...^
    596160796038a298 a55e596160796038 | Ya`y`8...^Ya`y`8
    61607960206d72c7 6238623861607960 | a`y` mr.b8b8a`y`
    20a26a816220a26a 81a298a55e596220 |  .j.b .j....^Yb
    a26a81a298a55e59 a298a55e59616079 | .j....^Y...^Ya`y
    60386220a26a81a2 9836653861607960 | `8b .j...6e8a`y`
    20a26a8162386160 796020a26a816220 |  .j.b8a`y` .j.b
    a26a81a298a55e59 6238a298a55e5961 | .j....^Yb8...^Ya
    6079603861607960 20a26a8162386160 | `y`8a`y` .j.b8a`
    7960a26a816220a2 6a81a298a55e5962 | y`.j.b .j....^Yb
    386160796020a26a 816220a26a81a298 | 8a`y` .j.b .j...
    a55e596220a26a81 a298a55e59a298a5 | .^Yb .j....^Y...
    5e59613862386220 a26a81           | ^Ya8b8b .j.
TRACE +0.000 Remaining data in serial buffer:
    a298a55e59a298a5 5e596160796038a2 | ...^Y...^Ya`y`8.
    98a55e5961607960 3861607960       | ..^Ya`y`8a`y`
.TRACE +0.094 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.000 Read 235 bytes:
    6a81a298a55e5962 38a298a55e596160 | j....^Yb8...^Ya`
    7960386160796020 a26a816238616079 | y`8a`y` .j.b8a`y
    6020a26a816220a2 6a81a298a55e5962 | ` .j.b .j....^Yb
    386160796020a26a 816220a26a81a298 | 8a`y` .j.b .j...
    a55e596220a26a81 a298a55e59a298a5 | .^Yb .j....^Y...
    5e59613862386220 a26a81a298a55e59 | ^Ya8b8b .j....^Y
    a298a55e59616079 6038a298a55ea298 | ...^Ya`y`8...^..
    a55e59a298a55e59 61607960386220a2 | .^Y...^Ya`y`8b .
    6a81a298a55e59a2 98a55e5961607960 | j....^Y...^Ya`y`
    38a298a55e596160 7960386160796020 | 8...^Ya`y`8a`y`
    a26a8162386220a9 6e59616079603861 | .j.b8b .nYa`y`8a
    60796020a26a8162 386160796020a26a | `y` .j.b8a`y` .j
    816220a26a81a298 a55e596238616079 | .b .j....^Yb8a`y
    6020a26a816220a2 6a81a298a55e5962 | ` .j.b .j....^Yb
    20a26a81a298a55e 59a298           |  .j....^Y..
TRACE +0.016 Read invalid data:
    6a81a298a55e5962 38a298a55e596160 | j....^Yb8...^Ya`
    7960386160796020 a26a816238616079 | y`8a`y` .j.b8a`y
    6020a26a816220a2 6a81a298a55e5962 | ` .j.b .j....^Yb
    386160796020a26a 816220a26a81a298 | 8a`y` .j.b .j...
    a55e596220a26a81 a298a55e59a298a5 | .^Yb .j....^Y...
    5e59613862386220 a26a81a298a55e59 | ^Ya8b8b .j....^Y
    a298a55e59616079 6038a298a55ea298 | ...^Ya`y`8...^..
    a55e59a298a55e59 61607960386220a2 | .^Y...^Ya`y`8b .
    6a81a298a55e59a2 98a55e5961607960 | j....^Y...^Ya`y`
    38a298a55e596160 7960386160796020 | 8...^Ya`y`8a`y`
    a26a8162386220a9 6e59616079603861 | .j.b8b .nYa`y`8a
    60796020a26a8162 386160796020a26a | `y` .j.b8a`y` .j
    816220a26a81a298 a55e596238616079 | .b .j....^Yb8a`y
    6020a26a816220a2 6a81a298a55e5962 | ` .j.b .j....^Yb
    20a26a81a298a55e 59a298           |  .j....^Y..
TRACE +0.000 Remaining data in serial buffer:
.TRACE +0.094 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.000 Read 205 bytes:
    6079603862386160 796020a26a816220 | `y`8b8a`y` .j.b
    a26a81a298a55e59 6220a26a81a298a5 | .j....^Yb .j....
    5e59a298a55e5961 607960386220a26a | ^Y...^Ya`y`8b .j
    81a298a55e59a298 a55e596160796038 | ....^Y...^Ya`y`8
    a298a55e59616079 60386160796020a2 | ...^Ya`y`8a`y` .
    6a81623862386160 796020a26a816220 | j.b8b8a`y` .j.b
    a26a81a298a55e59 62a26a81a298a55e | .j....^Yb.j....^
    59a298a55e596160 7960386220a26a81 | Y...^Ya`y`8b .j.
    a298a55e59a298a5 5e596160796038a2 | ...^Y...^Ya`y`8.
    98a55e5961607960 386160796020a26a | ..^Ya`y`8a`y` .j
    8162e1a298a55e59 6160796038616079 | .b....^Ya`y`8a`y
    6020a26a81623861 60796020a26a8162 | ` .j.b8a`y` .j.b
    20a26a81a298a55e 5962386160       |  .j....^Yb8a`
TRACE +0.016 Read invalid data:
    6079603862386160 796020a26a816220 | `y`8b8a`y` .j.b
    a26a81a298a55e59 6220a26a81a298a5 | .j....^Yb .j....
    5e59a298a55e5961 607960386220a26a | ^Y...^Ya`y`8b .j
    81a298a55e59a298 a55e596160796038 | ....^Y...^Ya`y`8
    a298a55e59616079 60386160796020a2 | ...^Ya`y`8a`y` .
    6a81623862386160 796020a26a816220 | j.b8b8a`y` .j.b
    a26a81a298a55e59 62a26a81a298a55e | .j....^Yb.j....^
    59a298a55e596160 7960386220a26a81 | Y...^Ya`y`8b .j.
    a298a55e59a298a5 5e596160796038a2 | ...^Y...^Ya`y`8.
    98a55e5961607960 386160796020a26a | ..^Ya`y`8a`y` .j
    8162e1a298a55e59 6160796038616079 | .b....^Ya`y`8a`y
    6020a26a81623861 60796020a26a8162 | ` .j.b8a`y` .j.b
    20a26a81a298a55e 5962386160       |  .j....^Yb8a`
TRACE +0.000 Remaining data in serial buffer:
    796020a26a816220 a26a81a298a55e59 | y` .j.b .j....^Y
    6220a26a81a298a5 5e               | b .j....^
.TRACE +0.249 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.016 Read 235 bytes:
    8162386160796020 a26a816220a26a81 | .b8a`y` .j.b .j.
    a298a55e596238a2 98a55e5961607960 | ...^Yb8...^Ya`y`
    386160796020a26a 8162386160796020 | 8a`y` .j.b8a`y`
    a26a816220a26a81 a298a55e59623861 | .j.b .j....^Yb8a
    60796020a26a8162 20a26a81a298a55e | `y` .j.b .j....^
    596220a26a81a298 a55e59a298a55e59 | Yb .j....^Y...^Y
    61607960386238a2 98a55e596160794e | a`y`8b8...^Ya`yN
    20a26a81a298a55e 596220a26a81a298 |  .j....^Yb .j...
    a55e59a298a55e59 61607960386220a2 | .^Y...^Ya`y`8b .
    6a81a298a55e59a2 98a55e5961607960 | j....^Y...^Ya`y`
    38a298a55e596160 a31681a26a81a298 | 8...^Ya`....j...
    a55e596238a298a5 5e59616079603861 | .^Yb8...^Ya`y`8a
    60796020a26a8162 386160796020a26a | `y` .j.b8a`y` .j
    816220a26a81a298 a55e596238616079 | .b .j....^Yb8a`y
    6020a26a816220a2 6a81a2           | ` .j.b .j..
TRACE +0.000 Read invalid data:
    8162386160796020 a26a816220a26a81 | .b8a`y` .j.b .j.
    a298a55e596238a2 98a55e5961607960 | ...^Yb8...^Ya`y`
    386160796020a26a 8162386160796020 | 8a`y` .j.b8a`y`
    a26a816220a26a81 a298a55e59623861 | .j.b .j....^Yb8a
    60796020a26a8162 20a26a81a298a55e | `y` .j.b .j....^
    596220a26a81a298 a55e59a298a55e59 | Yb .j....^Y...^Y
    61607960386238a2 98a55e596160794e | a`y`8b8...^Ya`yN
    20a26a81a298a55e 596220a26a81a298 |  .j....^Yb .j...
    a55e59a298a55e59 61607960386220a2 | .^Y...^Ya`y`8b .
    6a81a298a55e59a2 98a55e5961607960 | j....^Y...^Ya`y`
    38a298a55e596160 a31681a26a81a298 | 8...^Ya`....j...
    a55e596238a298a5 5e59616079603861 | .^Yb8...^Ya`y`8a
    60796020a26a8162 386160796020a26a | `y` .j.b8a`y` .j
    816220a26a81a298 a55e596238616079 | .b .j....^Yb8a`y
    6020a26a816220a2 6a81a2           | ` .j.b .j..
TRACE +0.000 Remaining data in serial buffer:
.TRACE +0.096 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 No serial data received.
.TRACE +0.091 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.125 No serial data received.
.TRACE +0.091 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.016 Read 50 bytes:
    0d0a20657473204a 616e202038203230 | .. ets Jan  8 20
    31332c7273742063 61cd95e9322c2062 | 13,rst ca...2, b
    6f6f74206d6f6465 3a28312c36290d0a | oot mode:(1,6)..
    0d0a                              | ..
TRACE +0.000 Read invalid data:
    0d0a20657473204a 616e202038203230 | .. ets Jan  8 20
    31332c7273742063 61cd95e9322c2062 | 13,rst ca...2, b
    6f6f74206d6f6465 3a28312c36290d0a | oot mode:(1,6)..
    0d0a                              | ..
TRACE +0.000 Remaining data in serial buffer:
.TRACE +0.094 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 No serial data received.
.TRACE +0.754 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.100 No serial data received.
.TRACE +0.100 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.100 No serial data received.
.TRACE +0.100 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.100 No serial data received.
.TRACE +0.085 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.016 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.000 Read 51 bytes:
    0d0a20657473204a 616e202038203230 | .. ets Jan  8 20
    31332c7273742063 617573653a322c20 | 13,rst cause:2,
    626f6f74206d6f64 653a28312c36290d | boot mode:(1,6).
    0a0d0a                            | ...
TRACE +0.000 Read invalid data:
    0d0a20657473204a 616e202038203230 | .. ets Jan  8 20
    31332c7273742063 617573653a322c20 | 13,rst cause:2,
    626f6f74206d6f64 653a28312c36290d | boot mode:(1,6).
    0a0d0a                            | ...
TRACE +0.000 Remaining data in serial buffer:
.TRACE +0.100 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.100 No serial data received.
.TRACE +0.247 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.116 No serial data received.
.TRACE +0.091 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.125 No serial data received.
.TRACE +0.091 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.016 Read 20 bytes:
    0d0a20657473204a 616e202038203230 | .. ets Jan  8 20
    31332c72                          | 13,r
TRACE +0.000 Read invalid data:
    0d0a20657473204a 616e202038203230 | .. ets Jan  8 20
    31332c72                          | 13,r
TRACE +0.000 Remaining data in serial buffer:
.TRACE +0.100 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.047 Read 1 bytes: 72
TRACE +0.000 Read invalid data: 72
TRACE +0.000 Remaining data in serial buffer: 662063616c20736563746f723a20
.TRACE +0.099 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.016 Read 234 bytes:
    20a26a816220a26a 81a2386238a298a5 |  .j.b .j..8b8...
    5e59616079603861 60796020a26a8162 | ^Ya`y`8a`y` .j.b
    386160796020a26a 816220a26a81a298 | 8a`y` .j.b .j...
    a55e596238616079 6020a26a816220a2 | .^Yb8a`y` .j.b .
    6a81a298a55e5962 20a26a81a298a55e | j....^Yb .j....^
    59a298a55e59617a 9068f16970992478 | Y...^Yaz.h.ip.$x
    f9ead92c857128d1 aa386238a298a55e | ...,.q(..8b8...^
    59615e59a298a55e 596160796038a298 | Ya^Y...^Ya`y`8..
    a55e596160796038 6160796020a26a81 | .^Ya`y`8a`y` .j.
    6238a298a55e5961 6079603861607960 | b8...^Ya`y`8a`y`
    20a26a8162386160 7960206079603861 |  .j.b8a`y` `y`8a
    6079602062386220 a26a81a298a55e59 | `y` b8b .j....^Y
    a298a55e59616079 6038a298a55e5961 | ...^Ya`y`8...^Ya
    6079603861607960 20a26a816238a298 | `y`8a`y` .j.b8..
    a55e596160796038 6160             | .^Ya`y`8a`
TRACE +0.000 Read invalid data:
    20a26a816220a26a 81a2386238a298a5 |  .j.b .j..8b8...
    5e59616079603861 60796020a26a8162 | ^Ya`y`8a`y` .j.b
    386160796020a26a 816220a26a81a298 | 8a`y` .j.b .j...
    a55e596238616079 6020a26a816220a2 | .^Yb8a`y` .j.b .
    6a81a298a55e5962 20a26a81a298a55e | j....^Yb .j....^
    59a298a55e59617a 9068f16970992478 | Y...^Yaz.h.ip.$x
    f9ead92c857128d1 aa386238a298a55e | ...,.q(..8b8...^
    59615e59a298a55e 596160796038a298 | Ya^Y...^Ya`y`8..
    a55e596160796038 6160796020a26a81 | .^Ya`y`8a`y` .j.
    6238a298a55e5961 6079603861607960 | b8...^Ya`y`8a`y`
    20a26a8162386160 7960206079603861 |  .j.b8a`y` `y`8a
    6079602062386220 a26a81a298a55e59 | `y` b8b .j....^Y
    a298a55e59616079 6038a298a55e5961 | ...^Ya`y`8...^Ya
    6079603861607960 20a26a816238a298 | `y`8a`y` .j.b8..
    a55e596160796038 6160             | .^Ya`y`8a`
TRACE +0.000 Remaining data in serial buffer:
    796020a26a816238 6160796020a26a81 | y` .j.b8a`y` .j.
    6220a26a81a2c06a 744e386220a2     | b .j...jtN8b .
.

A fatal error occurred: Failed to connect to ESP8266: Invalid head of packet (0x20): Possible serial noise or corruption.
For troubleshooting steps visit: https://docs.espressif.com/projects/esptool/en/latest/troubleshooting.html

More Information

The boot mode is (1,6) - is this a problem? It appears that the command receives data, but it doesn't seem to process it.

Other Steps to Reproduce

No response

I Have Read the Troubleshooting Guide

• [x] I confirm I have read the troubleshooting guide.

[Honza0297]

Hello @radio-satellites!

Most of the output is esptool trying to sync with the board. Synchronization happens a few times, but is lost very quickly. Sometimes, the board enters FW download mode (boot mode (1,6)), sometimes, the board starts to output invalid data (.j.b .j..8b8.... etc). Your board is probably not able to stay in the FW download mode.

This is almost certainly not a SW issue, but rather a HW one.

First of all, do you have the required pins in correct states when booting?

• GPIO15 pulled-down - I see you are using this pin, so please pay extra attention to this.
• GPIO2 pulled-up

If yes, try to open serial monitor (e.g. python -m esp_idf_monitor -b 78400) with

• GPIO0 pull down. This should get the board into FW download mode and some info might be printed out in the monitor.
• GPIO0 pulled up. This should enter normal boot and application might write something to the serial port. If the text will be gibberish, try other baudrates (9600, 115200...)

[radio-satellites]

Hi @Honza0297!

Thanks for your reply! I just noticed it now. I'm not sure why GitHub isn't sending me emails anymore...

Yes, both GPIO15 and GPIO2 are pulled LOW, or at least both have pull-down resistors placed on the PCB. I did check with a multimeter, and for some reason GPIO15 reads positive (although it is connected to a 10k pull-down?). I connected it to ground via a jumper and it still doesn't want to flash, unfortunately. GPIO15 is used as NSEL for the Si4432 SPI interface (which should be LOW anyways).

Yes, the GPIO0 modes are as expected. GPIO0 to GND outputs the expected flash state but pulled up boots into the regular default firmware.

[Honza0297]

Thanks for your answer!

...both GPIO15 and GPIO2 are pulled LOW...

GPIO02 should be pulled UP (see the table here: https://docs.espressif.com/projects/esptool/en/latest/esp8266/advanced-topics/boot-mode-selection.html#required-pins ). If it is pulled LOW, it may be the culprit we are looking for.

[radio-satellites]

@Honza0297 That was a typo on my part. I meant GPIO0. I'll double check GPIO2 in a sec...

[radio-satellites]

Here's the schematic for the ESP8266 section, by the way

[radio-satellites]

Not sure what happened... but...

Thank you so much @Honza0297!

[radio-satellites]

Guess I'll have to reopen...

Worked fine until all of a sudden:

Serial port COM9
Connecting...TRACE +0.000 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.111 Timed out waiting for packet header
.TRACE +0.102 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.001 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.114 Timed out waiting for packet header
.TRACE +0.104 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.001 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.113 Timed out waiting for packet header
.TRACE +0.105 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.002 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.112 Timed out waiting for packet header
.TRACE +0.104 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.001 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.115 Timed out waiting for packet header
.TRACE +1.905 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.002 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.113 Timed out waiting for packet header
_TRACE +0.103 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.003 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.002 Read 1 bytes: c0
TRACE +0.004 Read 1 bytes: 01
TRACE +0.000 Read 10 bytes: 000200000000000105c0
TRACE +0.000 Received full packet: 01000200000000000105

A fatal esptool.py error occurred: Invalid (unsupported) command 0x8
C:\Users\sasha>C:\Users\sasha\AppData\Local\Arduino15\packages\esp8266\tools\python3\3.7.2-post1/python3 -I C:\Users\sasha\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.1.2/tools/upload.py --chip esp8266 --port COM9 --baud 78400 --before default_reset --after hard_reset write_flash 0x0 C:\Users\sasha\AppData\Local\Temp\arduino_build_939187/sketch_oct18a.ino.bin --trace
esptool.py v3.0
Serial port COM9
Connecting...TRACE +0.000 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.001 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.110 Timed out waiting for packet header
.TRACE +0.102 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.002 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.113 Timed out waiting for packet header
.TRACE +0.102 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.001 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.116 Timed out waiting for packet header
.TRACE +0.102 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.002 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.114 Timed out waiting for packet header
.TRACE +0.104 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.001 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.116 Timed out waiting for packet header
.TRACE +1.897 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.002 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.110 Timed out waiting for packet header
_TRACE +0.102 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.002 Write 46 bytes:
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.003 Read 1 bytes: c0
TRACE +0.000 Read 11 bytes: 01000200000000000105c0
TRACE +0.001 Received full packet: 01000200000000000105

A fatal esptool.py error occurred: Invalid (unsupported) command 0x8

[Honza0297]

Let's debug further. Can you desolder the Si442 temporarily? I see you stated:

GPIO15 reads positive (although it is connected to a 10k pull-down?).

which may indicate an issue on the Si442 side.

[Honza0297]

Another though: I see you are switching between esptool 4.8 and 3.0. Does the behavior differ (e.g. in the frequency of errors etc.) between those two versions?

[radio-satellites]

Nope, it looks about the same.

I'm wondering at this point if it's the reliability of the UART connection - I've gotten it to flash sometimes, but other times it just inexplicably fails.

[radio-satellites]

UART is connected via 2.54mm headers into jumper wires, which I then plug into a USB to UART converter.

[Honza0297]

You can try to switch cables to rule out possible issues with the wires, but generally speaking, jumper wires are good enough for UART communication, if no other issue is in play.

I am still wondering how HIGH value got on GPIOI15 before you shorted it directly to GND. Please let me know if you are able to flash the ESP8266 without Si4432 soldered.

[radio-satellites]

Yes, the chip flashes equally sometimes with and without the Si4432.

Sometimes, changing jumper wires helps, but not always.

[radio-satellites]

Another debug output from a failed flash:

esptool.py v3.0
Serial port /dev/ttyACM0
Connecting...TRACE +0.000 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +1.804 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.036 Read 1 bytes: 73
TRACE +0.000 Read invalid data: 73
TRACE +0.000 Remaining data in serial buffer: 
    6c006c9c9e7c008c 6ce07c030c0c0c8c | l.l..|..l.|.....
    0c6cec0c637c8e83 02               | .l..c|...
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.204 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.043 Read 1 bytes: 73
TRACE +0.000 Read invalid data: 73
TRACE +0.000 Remaining data in serial buffer: 
    6c006c9c9e7c008c 6ce07c030c0c0c8c | l.l..|..l.|.....
    0c                                | .
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +1.804 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.104 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.204 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.083 Read 1 bytes: 72
TRACE +0.000 Read invalid data: 72
TRACE +0.000 Remaining data in serial buffer: 
    6c006c9c9f7c008c 6ce07c020c0c0c8c | l.l..|..l.|.....
    0c6cec0c627c8f82 03ec12937293628c | .l..b|......r.b.
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +1.804 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.105 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.025 Read 1 bytes: 00
TRACE +0.000 Read invalid data: 00
TRACE +0.000 Remaining data in serial buffer: c000000000000000
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.203 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.094 Read 1 bytes: 72
TRACE +0.000 Read invalid data: 72
TRACE +0.000 Remaining data in serial buffer: 6c006c
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +1.804 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.104 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.104 Timed out waiting for packet header
_TRACE +0.203 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.104 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.104 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.104 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +1.804 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.102 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.203 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.002 Read 1 bytes: 73
TRACE +0.000 Read invalid data: 73
TRACE +0.000 Remaining data in serial buffer: 
    6c006c9c9e7c008c 6ce07c030c0c0c8c | l.l..|..l.|.....
    0c6cec                            | .l.
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +1.804 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.030 Read 1 bytes: 72
TRACE +0.000 Read invalid data: 72
TRACE +0.000 Remaining data in serial buffer: 
    6c006c9c9e7c008c 6ce07c020c0c0c8c | l.l..|..l.|.....
    0c6cec0c627c8f82 03ec12937293638c | .l..b|......r.c.
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.105 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.105 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.203 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
.TRACE +1.804 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.069 Read 1 bytes: 72
TRACE +0.000 Read invalid data: 72
TRACE +0.000 Remaining data in serial buffer: 
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_TRACE +0.051 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
    0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    55555555                          | UUUU
TRACE +0.000 Write 46 bytes: 
    c000082400000000 0007071220555555 | ...$........ UUU
    5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
    5555555555555555 5555555555c0     | UUUUUUUUUUUUU.
TRACE +0.101 Timed out waiting for packet header
_

A fatal error occurred: Failed to connect to ESP8266: Timed out waiting for packet header

[Honza0297]

If all the pins are in correct states, this is most likely a HW issue, not an issue with esptool.

You can send your PCB design for free-of-charge review: https://www.espressif.com/en/contact-us/circuit-schematic-pcb-design-review , where our engineers will check if the PCB design is correct.

We are closing the issue for now.

[radimkarnis]

@radio-satellites esptool requires a working serial connection to operate. Without it, there is not much we can do on the software side. Please try to inspect your serial chain again (e.g. use miniterm or esp-idf-monitor to open a console and see what output (if any) you get in certain cases).

We'll close this in the meantime. Feel free to reopen if you get more information.

[radio-satellites]

@radimkarnis Yes, UART is definitely working and reliable. I'm consistently getting an output every time which indicates the boot mode and cause when GPIO0 is set to LOW and RST is triggered.

[radio-satellites]

I finally found the issue. It is incredibly simple: sometimes, the GPS (using UART0) would not shutdown before flashing, preventing the data from reaching the MCU. That's it!