ESP32 boot partitions

[proddy]

When a firmware is uploaded via the WebUI it rotates between the two app partitions called ota_0 and ota_1. See here for the names and addresses.

However if you manually use PlatformIO or esptool it will upload the firmware to the boot partition, so that when EMS-ESP starts up it won't be using the new firmware we just uploaded since the bootloader is still pointing to one of the ota_* partitions. This was driving me mad for a while having to do a restart boot from EMS-ESP's console.

We could probably fix this by adding board_upload.offset_address = 0x10000 to platformio.ini (10000 is the address of the boot/factory partition) but I have yet to test it.

Another option is to erase the app partitions first, but keep the flash intact, but not sure if that is possible. @MichaelDvP any ideas?

[MichaelDvP]

The boot partition is stored in ota_data partition (0xE000-0xFFFF). I think we need to erase this.
esptool has a option erase_region, but i don't know how to configure in pio.
Command is esptool.py erase_region 0xE000 0x2000 (paramters: start, length)

[proddy]

Yes, I think that's the way. Uploading via platformio will always use ...platformio/packages/framework-arduinoespressif32/tools/partitions/boot_app0.bin so putting the app in app0, when we want it to be where the active ota partition is (could be app1). Easiest way is to indeed remove the ota_data so it defaults to the factory partition. I think the way to do this is in a script like

Import("env", "projenv")
def ereaseOTA(source, target, env):
    env.Execute("python esptool.py erase_region 0xE000 0x2000")
env.AddPreAction("upload", ereaseOTA)

I also found another python script that does it, called otatool and then use python to call target.erase_otadata(). https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/system/ota.html#python-api

[MichaelDvP]

Alternative for own testing: put in your pio_local.ini:
board_build.app_partition_name = app0

this flashes to app0 and boots from app0