esp32s3 - combining tinyuf2 and application

[rtborg]

Is it possible to merge tinyuf2 and application binaries in a single binary, which can then be flashed via DFU or UART?

[tannewt]

Yes, you can use objcopy to merge binaries.

[tannewt]

@makermelissa May know. I think she's done it for the web loader.

[makermelissa]

I'm not sure what you're trying to do. For the web loader, it either flashed tinyuf2 (using combined.bin file from the release) and then installed the circuitpython UF2 into flash memory or it just installed the circuitpython.bin file, but it was never combined with tinyuf2.

[rtborg]

I'm trying to use idf.py write-flash for flashing the tinyuf2 binaries and the application binary in one step. It fails - the device stays in tinyUF2.
The flash dump of a working tinyUF2 + application reveals some data at 0xe000 (ota_data_initial.bin). I don't have access to my PC now, but tomorrow I'll check if tinyUF2 is reading/writing there.

[hathach]

you will need to mark the ota0 partition as valid for it to boot. It is simply 0x0001 ircc. If you use Ardduino it is called boot_app0 bin

[rtborg]

That did the job, thank you for the input.

I examined the data at 0xe000, and in addition to 0x01 there are some bytes at 0xE01C, namely 0x9a984347. These bytes are found in both boot_app0.bin, and in the flash dump of a working tinyuf2+application. I initially assumed that was CRC of the ota0 partition, but that's likely wrong.

In any case, the bootloader binaries can be combined with application binary, and then flashed together.