@Max
Thanks Max.
Unfortunately I don't know how to debug the board, so I'll leave that to someone that knows.
I'm am already running minimal setup - I have only radio and motors connected (and a DIMU of course). I can freeze the board without serial connected too. I can also try to crash it without motors connected, but what's the point of building a copter without motors?
@Adam
I'll be glad to send the board to whoever wants a malfunctioning board, but that depends if Jussi wants it back or not. Actually it depends on weather he will send me a new board at all - so far he is reluctant to even reply to my messages.
Thanks for trying to help, guys!
-Mateusz