Start download mode on ESP32 without hard reset

[rbhagwat62]

Hello,

In my current project, ESP32 is connected with another Microcontroller. ESP32's flashing UART pins are connected with microcontroller one of UART. We need to flash ESP32 using microcontroller. In current hardware ESP EN pin and second microcontroller reset pin are connected together with Pullup resistor meaning we don't have any controller on the ESP32 EN pin.

Now we want to start download mode on ESP32 by soft resetting the ESP32 through some UART commands.

We tried to pull down boot pin of ESP32 and soft reset but it doesn't start download mode.

We find some commands through which we can start ESP in boot mode after soft reset, but it is applicable to ESP32-C2,C3 and ESP32-S2,S3 only.

Is there any way we can start download mode on ESP32 with soft reset Or is there any way we can do firmware update on ESP32 using UART.

Also can we change default flashing UART pins in bootloader, if yes where I can find documentation.

Thanks.