1. Have you calibrated MAG?
2. Turn off MAG (set mag_hardware = 1)... I think from 1.7.2 its 1, before was 3, if i remember correctly) and try again.
2. Turn off MAG (set mag_hardware = 1)... I think from 1.7.2 its 1, before was 3, if i remember correctly) and try again.