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esp32

Flashing ESP32's memory without installing the whole IDF?

Problem

I'm looking for a way to flash an ESP32 module's memory without installing the whole IDF software suite.

Why

Because I want to integrate ESP32 onto a custom board along with a low-performance ARM-powered CPU which runs a tiny Linux distro (based on Debian), and I want to flash ESP32 from this tiny Linux distro.

I know I could use the bootloader, but who will upload the initial bootloader? I don't want to do extra steps, so my idea is to embed the ESP32 module onto my custom board, and let the Linux to flash it from factory-state (when it's flash is empty, ie. no preloaded bootloader). Or is the serial bootloader always preinstalled on all ESP32 modules (like on ESP-WROOM-32)?

Why I don't want to use IDF? Because I don't want to build or debug anything, I just want to flash myprogram.bin onto ESP32. Also, as the board is low-performance, it would take ages to download everything for running IDF.

Current state

The ESP32 module is now visible via UART (RX,TX,GND), and if I held low the GPIO0, it runs the bootloader (my current module is embedded onto a NodeMCU - but there is no USB connected, this is raw UART!):

rst:0x1 (POWERON_RESET),boot:0x3 (DOWNLOAD_BOOT(UART0/UART1/SDIO_REI_REO_V2))

waiting for download

Could I expect the same behavior (controlling GPIO0 for running the bootloader) for all ESP32 modules, or this works just because guys at NodeMCU preprogrammed already some bootloader onto it?

I'm looking for a way to flash this ESP32 preferrably without any python script.

Solution

  • Actually Espressif also provides a nice and small binary for flashing ESPs:

    https://github.com/espressif/esp-serial-flasher

    Serial flasher component provides portable library for flashing Espressif SoCs (ESP32, ESP32-S2, ESP8266) from other host microcontroller. Espressif SoCs are normally programmed via serial interface (UART). Port layer for given host microcontroller has to be implemented, if not available.

    One more (but very important) addition: You have to modify this repo to make it work correctly, and also you might have to upload not just your binary, but also bootloader and partition_table.