enable write cahceing but do not enable the bottom option, that should be fine. Tbh i have no battery and i run write back all the time. i have not had any issues, however with some instability issues i think you should stay with the write through. i would change to cache on the MSM though. both of those options should be fine without jurting anything. i believe the problem is your board, or issues with your device you were plugging in.