I have a 4S, not sure what happened, but phone rebooted, could not get it our of "safe mode". Have not installed tweek lately so did not think it was that. I have simple passcode turned off, and have a passcode of 4 digits. When I would try to get out of safe mode, started putting in passcode, phone would lock up on 3rd digit....... so, I shortened passcode to 2 digits. Now works, came out of safe mode. Anyway, not sure what was happening, it was like something was timing out. Just thought I would share