Answer to: iPhone 3GS randomly crashes, then reboots into "no power" screen@se7en : I have been fighting the black screen crashes since June. I can honestly say that I had absolutely no issue whatsoever with my 3GS until I upgraded it to iOS 4.x. After the upgrade was when it would suddenly start crashing on me. I did try shutting off the 3G and the phone did work okay after that - for a couple of days. It crashes on Edge no matter what now, with Wifi and BT all shut off, no apps running, etc. If I plug it into the wall, it's fine but it heats up something fierce. I'm pretty confident it's the battery/battery sensor being shot as when the phone crashes (sometimes at "100%") and turns back on it always is a different percentage (ie, 100% to 77% to 84% ...yes, I have had it jump like that consecutively). Just ordered my new battery so I'll report back after the replacement on whether or not it still crashes.