Can anyone help me, I’m using the Multiwii and Megapirate AIO Flight Controller w/FTDI (ATmega 2560) V2.0 from Hobbyking, everything worked fine previously, but Ive recently reflashed the firmware on the board as I changed something before messing around with waypoints & return to home etc, anyway long story short its got Megapirate 3.0.1-R4 on it I’m using MP 1.3.7.4 build 1.1.5340.35674 my problem is it just wont calibrate the compass just keeps coming up with compass offsets too high when I try & arm it can anyone tell me how to get round this please, many thanks 
please post a photo of your setup. move any cables/wires/metal away from the mag