There may/may not be a common element with the problem I experienced. My 9550 worked perfectly for about 10 days, then began rebooting itself. I first noticed it when driving on a bumpy gravel road; it happened several times when I pulled the USB charging cable; it happened lightly squeezing the touchscreen; it would happen reliably if I dropped the phone 1/2 - 1 inch flat onto a counter top. I concluded that it was behaving just like a battery pull maneuver each time. I suspected an intermittent electrical disconnect between the battery and the circuitry. I took the phone back to a Verizon store, traded for a new 9550, and have had no further issues. My problem may have been a unique one, or perhaps there is a build-quality issue with the 9550?