ESP32 Forum

Hi. I have a custom ESP32-C3 WROOM based board that I need to flash firmware and I was looking to use the esp-serial-flasher but it looks like this is meant to use the IO0 and RESET pins. I don't have direct access to these pins, since I put the auto programming circuit (the BJT's with the resistors) so I can use a USB-to-UART device to flash the boards.

Is there way I can use the esp-serial-flasher tool with the auto programming circuitry?

Sure. The low-level interface for esp-serial-flasher that poke IO0 and EN are loader_port_enter_bootloader() and (optionally, if your program wants to call that) loader_port_reset_target(). You can simply implement those with code that does the right DTR/RTS dance to make the two BJTs do the indicated things.