MicroPython -> Cannot access Serial REPL Prompt after successful reflashing (ESPTOOL-245)

[ghost]

Operating system

Ubuntu 18.04

Python version

Can run python -V to check this.

2.7.17

What Chip

(For example: ESP8266, ESP32-PICO-D4, ESP32-WROOM32 module, etc)

ESP8266

What development board or other hardware is the chip attached to

(For example: DevKitC, NodeMCU board, plain module on breadboard, etc)

If your hardware is custom or unusual, please attach a photo to the issue.

NodeMCU

Is anything else attached to the development board, except for the serial flasher connections?

Example: GPIO 18 & 19 are connected to I2C devices.

No.

Are you running esptool.py from an IDE such as Arduino or Eclipse?

No. I'm running esptool.py from my terminal.

Full esptool.py command line that was run:

1) sudo esptool.py --port /dev/ttyUSB0 erase_flash 2) sudo esptool.py --port /dev/ttyUSB0 write_flash --flash_size=detect 0 esp8266-20210418-v1.15.bin

Full output from esptool.py

1) esptool.py v2.0 Connecting.... Detecting chip type... ESP8266 Chip is ESP8266 Uploading stub... Running stub... Stub running... Erasing flash (this may take a while)... Chip erase completed successfully in 2.0s Hard resetting...

2) esptool.py v2.0 Connecting.... Detecting chip type... ESP8266 Chip is ESP8266 Uploading stub... Running stub... Stub running... Configuring flash size... Auto-detected Flash size: 4MB Flash params set to 0x0040 Compressed 632632 bytes to 415633... Wrote 632632 bytes (415633 compressed) at 0x00000000 in 36.8 seconds (effective 137.5 kbit/s)... Hash of data verified.

Leaving... Hard resetting...

Do you have any other information from investigating this?

I try to minicom into the device. I press enter multiple times. No MicroPython REPL prompt pops up. I've done this on both 115200 and 9600 baud.

Is there any other information you can think of which will help us reproduce this problem?

Nope.

[dobairoland]

Hi @toddparker3233. Maybe it is an access issue. I see that you are running esptool with sudo so probably minicom doesn't have access to the port neither.

It is not recommended to use sudo for these tools. You could add access to the serial port for your OS user. This is the related information from the README:

In Linux, the current user may not have access to serial ports and a "Permission Denied" error will appear. On most Linux distributions, the solution is to add the user to the dialout group with a command like sudo usermod -a -G dialout . Check your Linux distribution's documentation for more information.

You can check if the dialout group is the right one for you by running:

ls -al /dev/ttyUSB*

[radimkarnis]

Hello @toddparker3233, any update? have you been able to resolve your issue? Radim

[radimkarnis]

Closing this issue for inactivity. Feel free to reopen if further discussion is needed.

[Erkman84]

Hi, I have the (almost) the same issue: after flashing with micropython (Raspberry OS) i do not get any repl promt, and what is strange: i cannot upload any script (main.py, boot.py), In this case I used a ESP C3 module. But unfortunatelly with some esp8266 boards the same thing i cannot understand. Repeating myself: I successfully flashed every board (!) (mentioned like on the man pages) BUT for some models after that i cannot upload any code, picocom repl answers, but there is input seems to be freezd. I thought it is conneted with CH340 driver but the system is up-to-date, so no kernel problems should be tried on antoher ubuntu 18 up-to-date system but it seems not to be an issue with my system.

Other Example: Wemos D1 mini eps8266 V1 --> flash: ok, write script: ok. That's okay. Wemos D1 mini esp8266 V2 --> other chip (?): flash: ok, write script fails, no repl prompt in picocom.

Tried windows 7 (with updated driver) with putty to connect, also no repl promt for the selected devices.

Anyone an idea? Micropython 1.19 bin --> this should be also not the problem, with the non-problematic devices it's working fine.