Where to find information about how to flash the ESP32 ?

[Bruno_Orosys]

Hello all,

I just browsed what I think is the whole documentation for the ESP32-SOLO-1 and couldn't find definitive information on the protocole used to flash it.

I have a ESP32-DeKkitc-V4 with a ESP32-SOLO-1, and I did flash it using the USB to UART converter and idf.py.exe.
I compiled, flashed and ran a few code examples, no problem here.

But now I want to do the same thin, ie flash the ESP32-SOLO-1 module, without using a computer and USB communication. I want to flash it using the UART, from the main MCU on my board. And I can't seem to find information on how to do this.

[*] The ESP32-SOLO-1 datasheet mentions strapping pins, GPIO0 and 2, a "Booting Mode", with either "SPI" or "Download". But nothing more about that.
[*] The Reference manual mentions the existence of the GPIO_STRAP_REG register which is modified by the strapping pins, but doesn't mention anything on how it is used.
[*] The "Docs » API Guides » General Notes About ESP-IDF Programming" page of the ESP-IDF Programming Guide mentions the GPIO_STRAP_REG register, but instead of "SPI" and "Download", it mentions "UART" and "SDIO". Could be a typo, ok, but then it mentions "and wait for code to be downloaded", but nothing on how to actually download the code...

Could someone point me to a doc explaining the downloading protocol ?

[ESP_Sprite]

You might want to take a look at https://github.com/espressif/esp-serial-flasher