like also happen to my K850, I took a few shoots suddenly the phone hungs... i remove the bat. and put it back again... but the phone is BROD, i flash it and everything go back to normal, except that one left touch key won't function properly, I re-flash again using other FS and other ways that this forum suggest still same problem, so i decided to replace the keypad, then the problem is fix, but several month the phone become BROD again, then I re-flash again, the phone is fix, but the left touch key is bad again, I wonder is these a bug or what... that everytime my phone BROD and when I fix it I have to replace the keypad because its also broken. I already done this 3 times, and already bought 3 keypads for this phone.