espflash is not compatible with Secure Download mode

[ivmarkov]

Once Secure Download mode had been enabled on the MCU (by burning the relevant eFUSE bits), espflash is unable to flash a binary (or ELF) image anymore.

Note that this is not related to the stub loader, because I'm passing the --no-stub flag:

ivan@ivan-laptop:~$ espflash flash --no-stub --chip esp32s3 --flash-size 16mb ./my-firmware 
[2025-02-03T12:35:14Z INFO ] Serial port: '/dev/ttyUSB0'
[2025-02-03T12:35:14Z INFO ] Connecting...
Error: espflash::timeout

  × Error while connecting to device
  ╰─▶ Timeout while running ReadReg command

I've also tried various combinations of --before (and --after) reset sequences, but none of those did work.

Note that esptool is capable of flashing even when the chip is in a Secure Download mode.
The command to do so is something like:

esptools tool --chip esp32s3 --no-stub write_flash 0x10000 ./my-firmware.bin --flash_size 16mb --force 

... where the --force parameter does all the magic.

[ivmarkov]

Ah, I've already reported this as #726 !