@torsten, unless Athom comes up with an easier way to do this, you need to disconnect from power, open the case, locate the serial pin holes (3.3V, TX, RX, GND), connect a serial flasher (in 3.3V mode!) and use esptool to erase the flash, then write the bootloader and the firmware.
@torsten, unless Athom comes up with an easier way to do this, you need to disconnect from power, open the case, locate the serial pin holes (3.3V, TX, RX, GND), connect a serial flasher (in 3.3V mode!) and use esptool to erase the flash, then write the bootloader and the firmware.