Post-iOS4 upgrade problem: rebooting

Question

For the most part, I've had no problems at all with my iPhone since the update. I've done all the things I usually did with it before the update and no problems, except this one.
It reboots sporadically (4-5 times since I upgraded), under pretty specific conditions, which it didn't do before.
Each time it rebooted, it was plugged into the wall socket. It was fully charged (this has only happened, so far, in the morning, though this may only be an coincidence of timing). I was listening to playlist music in the background and doing something else (such as surfing the internet or playing a game). Everything is fine, no problems to speak of, and then the screen goes black and then the Apple logo appears. After about 20 seconds it starts up again.
Anybody else having this problem?

Answer 1

Hello up dated to os4 now phone will reboot by it's self happend today4-5 times was doing this with old soft ware to I have to believe it is hardware issue does it in my pocket does while on phone while recording vid playing grand theft auto does it out Side has done it in side in the ac. Has done it batt half full and full charge has not done it plugged in yet I'm sure it will I have had like a blue screen of death only apples is black and says panic I'm stuck lol or some thing I have had apple that shows up during start up turn green lol not kidding last time that happened it was pink