I feel your pain, and I wish that I could help, but I too am awaiting a response from the developers. The last I flew, I too had althold go all wonky on me, even after disabling the secondary compass. I’m assuming that it’s tied to a common compass variance issue: 3.4rc1 - #15 by i-copter
The thing that bugs me the most is that I was flying just fine about a week ago, and my foolish self hadn’t made a backup image before starting a fresh build 