All operations are under desktop linux
On uConsole keyboard back,there is a UART port which can be used with stm32flash to flash keyboard stock firmware
Especially when your keyboard met problem
here is the process:
- put the switch 1 ON
- connect uart with a fpc 6p connector 0.5mm to a serial-usb converter
- use stm32flash to flash bin file
- put the switch 1 OFF
Whole connection view

UART ports

3 is TX(PA9)
4 is RX(PA10)
1st pin of UART on board

Do not forget to also connect GND (ground) between the fpc 6p connector and the serial-usb converter.
Flashing command
You can get uconsole.kbd.0.4_48mhz.bin from https://github.com/clockworkpi/uConsole/tree/master/Bin
Normal flashing output