I've tried the FCC hack and it seems to be working well in urban environments (I usually don't fly further than 300m but I do appreciate a more stable signal). What I am worried about is that with a standard method of keeping the FCC hack (connecting the phone with the props already spinning) you skip over some of the important pre-flight checks (like compass calibration). I don't even know if you would get a warning that the compass is not calibrated. Does anyone know?