MultiWii

No, it doesn't happen for me with 1.9. I flew a lot of time with 1.9 before, and after this strange behavior with 2.0, I went back to 1.9, and I don't have anymore this problem. For my first flight, when things were all right with 2.0, I didn't flew a lot of consecutive time, maybe less than 2 minut...

For me "acc drift" problem is another problem, in my case my quadcopter suddenly lean onward (or suddenly drift). In the case of "acc drift", drift is more like a cumulative error, it's not sudden.

A problem with Nunchuck
viewtopic.php?f=8&t=1455

Yesterday I made two flight in level mode, the first one was fine and no problem at all. The second one, after maybe 2/3 minutes of normal flight (no looping, no hard turn, ...) my quadcopter suddenly lean onward by almost 45°making my quadcopter moving forward very fast. What I did to avoid a crash...