Good onya' OP! I had a near JB fatality with a friend's v1 iPhone that was JB, when it went to a black screen and just flickered on and off, then was stuck in the silver apple screen mode. (she was lucky that she selected to keep her silver apple logo v. going with the pineapple). Anyway, we explained that it was frozen and the Genius ran a restore on it, but it wouldn't reboot. We knew it was a JB iPhone, but they swapped it out without further investigation. Whew...😱