I have purchased a pile of SonOff POW modules that I want to flash with alternate firmware that supports MQTT.
All the instructions say to just connect an FTDI board and off you go. Only, I don't have one handy and it will take several days to get one.
Is there a way I can use one of my existing NodeMCU boards to connect to the SonOff POW board (knowing you can't have it connected to AC to program, etc...) to be able to load the firmware?
I was thinking of writing a simple RS232 bridge firmware to take the USB serial stream and route it to the external serial pins. Would that work?
Thanks
Robert