My xp2 did the same thing going from 3.00 to 3.11 (and 3.12). I tried reloading multiple times, including a fresh copy. I sent it in to Fuji Repair, and they said the main power board has to be replaced, at a cost of $400 with tax and shipping.
As a firmware developer, this feels like a hardware compatibility problem to me. I was an early adopter and probably have the earliest board revisions. I asked if they would attempt to fix this in a future update, and also if they could revert my firmware to 3.00. Both answers were “no”.
Needless to say, I am pretty upset. It means I am paying $2000 for this body. Pissed. Disgruntled.