Platformio 6.5.0 Flash Size Warning

[DAVe3283]

The problem

tl;dr Platformio 6.5.0 added a warning if there is a flash size mismatch with IDF config and ESPHome is not setting IDF flash size, only the board flash size.

Background: I am using ESP32-C6 which is not supported by the recommended Platformio version or ESP-IDF version, and have to run the latest to get it to work. There is no board file for my hardware, so I have to add some custom options:

esphome:
  name: esp32c6
  friendly_name: esp32c6
  platformio_options:
    board_upload.maximum_size: 4194304

# OLIMEX ESP32-C6-EVB actually has 512K RAM, 4MB flash
# platformio esp32-c6-devkitm-1 claims 320K RAM which appears wrong per the ESP32-C6 datasheet
# platformio esp32-c6-devkitc-1 has RAM right, but has 8MB flash, we actually have 4MB
# Use devkitc and fix flash

esp32:
  board: esp32-c6-devkitc-1 # at least until https://github.com/platformio/platform-espressif32/issues/1152 is added
  variant: esp32c6          # ditto ↑
  flash_size: 4MB
  framework:
    type: esp-idf
    version: latest # Need at least 5.1 for ESP32-C6
    platform_version: 6.5.0 # 6.4.0 added ESP32-C6 but failing on checksum, 6.5.0 works though!

Setting flash_size: 4MB doesn't appear to set the appropriate CONFIG_ESPTOOLPY_FLASHSIZE_xMB=y variable. In the build directory, sdkconfig.esp32c6 appears to have been configured for 2MB (no idea where that came from, the board file would be 8MB, and I specified 4MB):

# CONFIG_ESPTOOLPY_FLASHSIZE_1MB is not set
CONFIG_ESPTOOLPY_FLASHSIZE_2MB=y
# CONFIG_ESPTOOLPY_FLASHSIZE_4MB is not set
# CONFIG_ESPTOOLPY_FLASHSIZE_8MB is not set
# CONFIG_ESPTOOLPY_FLASHSIZE_16MB is not set
# CONFIG_ESPTOOLPY_FLASHSIZE_32MB is not set
# CONFIG_ESPTOOLPY_FLASHSIZE_64MB is not set
# CONFIG_ESPTOOLPY_FLASHSIZE_128MB is not set
CONFIG_ESPTOOLPY_FLASHSIZE="2MB"
# CONFIG_ESPTOOLPY_HEADER_FLASHSIZE_UPDATE is not set

This causes the compile to start off with the new warning:

Warning! Flash memory size mismatch detected. Expected 4MB, found 2MB!
Please select a proper value in your `sdkconfig.defaults` or via the `menuconfig` target!

You can work around the problem by manually specifying the appropriate CONFIG_ESPTOOLPY_FLASHSIZE_xMB value:

 esp32:
   board: esp32-c6-devkitc-1 # at least until https://github.com/platformio/platform-espressif32/issues/1152 is added
   variant: esp32c6          # ditto ↑
   flash_size: 4MB
   framework:
     type: esp-idf
     version: latest # Need at least 5.1 for ESP32-C6
     platform_version: 6.5.0 # 6.4.0 added ESP32-C6 but failing on checksum, 6.5.0 works though!
+    sdkconfig_options:
+      CONFIG_ESPTOOLPY_FLASHSIZE_4MB: y

This fixes sdkconfig.esp32c6 and silences the error:

# CONFIG_ESPTOOLPY_FLASHSIZE_1MB is not set
# CONFIG_ESPTOOLPY_FLASHSIZE_2MB is not set
CONFIG_ESPTOOLPY_FLASHSIZE_4MB=y
# CONFIG_ESPTOOLPY_FLASHSIZE_8MB is not set
# CONFIG_ESPTOOLPY_FLASHSIZE_16MB is not set
# CONFIG_ESPTOOLPY_FLASHSIZE_32MB is not set
# CONFIG_ESPTOOLPY_FLASHSIZE_64MB is not set
# CONFIG_ESPTOOLPY_FLASHSIZE_128MB is not set
CONFIG_ESPTOOLPY_FLASHSIZE="4MB"
# CONFIG_ESPTOOLPY_HEADER_FLASHSIZE_UPDATE is not set

I imagine that in addition to basing the partitions on the user-selected flash_size, ESPHome needs to set the appropriate CONFIG_ESPTOOLPY_FLASHSIZE_xMB=y flag.

Which version of ESPHome has the issue?

2023.12.7

What type of installation are you using?

Home Assistant Add-on

Which version of Home Assistant has the issue?

N/A

What platform are you using?

ESP32-IDF

Board

Olimex ESP32-C6-EVB

Component causing the issue

esp32

Example YAML snippet

No response

Anything in the logs that might be useful for us?

Warning! Flash memory size mismatch detected. Expected 4MB, found 2MB!
Please select a proper value in your `sdkconfig.defaults` or via the `menuconfig` target!

Additional information

No response

[luar123]

Same for ESP32-H2

[felipejfc]

Thanks for this. I managed to fix a SHA checksum error I would get during linking with this option

    sdkconfig_options:
      CONFIG_ESPTOOLPY_FLASHSIZE_4MB: y

[QuickJack]

I have created https://github.com/platformio/platform-espressif32/pull/1396 which should fix RAM size for esp32-c6-devkitm-1.

[jschneekloth]

Similar issue with esp32-c3-devkitm-1

[QuickJack]

Well. not exactly. The templates for esp32-c3-devkitc-02 and esp32-c3-devkitm-1 both specify 320k RAM whereas the ESP32-C3 has 400k RAM. So these templates are wrong as well.