@Dave_Jones If you physically re-flash the firmware via USB it will wipe out your stored WiFi credentials (and Konnected Cloud credentials if enabled). You can re-connect to wifi by connecting to the konnected-xxxxx fallback network then open 192.168.4.1. Right now there’s no way to use the dev branch with Konnected cloud but I may try to add that in the app in the future.
@slopster Could you share some logs from start-up and after sending a few commands via HA or the web interface? You can stream logs over the network either via browser or command line, see: remote logging how-to