Downgrade Firmware

Original authors @serrj-sv and @rezmus.

Solder UART

1. Open Gateway

2. Solder USB UART adapter (GND to GND, RX to TX, TX to RX)

3. Connect adapter to USB. UART setting: 38400 8n1, disable flow control

4. Power gateway with build-in USB power

Useful links

• https://community.home-assistant.io/t/xiaomi-mijia-smart-multi-mode-gateway-zndmwg03lm-support/159586/92
• https://community.home-assistant.io/t/xiaomi-mijia-smart-multi-mode-gateway-zndmwg03lm-support/159586/108
• https://github.com/AlexxIT/XiaomiGateway3/issues/87#issuecomment-719348076