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

[proddy]

hmm, I couldn't get that to work. It boots from app0 but the firmware is written to boot. I see from the pio logs during an upload:

Configuring flash size...
Flash will be erased from 0x00000000 to 0x00003fff...
Flash will be erased from 0x00008000 to 0x00008fff...
Flash will be erased from 0x0000e000 to 0x0000ffff...
Flash will be erased from 0x00010000 to 0x00230fff...
...
Compressed 2229744 bytes to 1449344...
Writing at 0x00010000... (1 %)
Writing at 0x00014e4a... (2 %)

which says it's erasing the otadata block that starts at e0000 and also putting the firmware in x10000 in boot, which is strange. I'll keep looking.

[MichaelDvP]

But you have missed the part where it writes to 0xe000 the boot_app0.bin. You have to erase the partition after write or modify the boot_app0.bin.
With setting board_build.app_partition_name = app0 it looks like this:

Auto-detected Flash size: 16MB
Flash will be erased from 0x00001000 to 0x00005fff...
Flash will be erased from 0x00008000 to 0x00008fff...
Flash will be erased from 0x0000e000 to 0x0000ffff...
Flash will be erased from 0x00490000 to 0x00652fff...
SHA digest in image updated
Compressed 16528 bytes to 11296...
Writing at 0x00001000... (100 %)
Wrote 16528 bytes (11296 compressed) at 0x00001000 in 0.5 seconds (effective 254.3 kbit/s)...
Hash of data verified.
Compressed 3072 bytes to 164...
Writing at 0x00008000... (100 %)
Wrote 3072 bytes (164 compressed) at 0x00008000 in 0.1 seconds (effective 460.0 kbit/s)...
Hash of data verified.
Compressed 8192 bytes to 47...
Writing at 0x0000e000... (100 %)
Wrote 8192 bytes (47 compressed) at 0x0000e000 in 0.1 seconds (effective 597.0 kbit/s)...
Hash of data verified.
Compressed 1844320 bytes to 1246266...
Writing at 0x00490000... (1 %)

[proddy]

the board_build.app_partition_name didn't work for me, it still always writes to 0x10000 (boot/factory).

What did work was board_upload.offset_address = 0x290000. I used pio run -t upload and looked at the esptool.py command line call it generated.

I found board_upload.offset_address from the platformio source code in https://github.com/platformio/platform-espressif32/blob/develop/builder/main.py#L237

maybe it's because I'm using pioardunio and not platformio ?