iPhone 4 Stuck on Apple Logo
I have an iPhone 4 that is still running iOS 4.0.1. The last thing I remember doing is removing AppSync because I was having trouble downloading anything from Cydia. Now when I boot up I get stuck at the Apple logo and spinning wheel. Eventually the phone shuts itself off and the cycle repeats.
I have tried something I read online - hard reset, plug into computer, hard reset, plug into wall socket, hard reset, and on and on until it supposedly boots, but that hasn't happened after several hours.
Is there anything else I can try before I have to give up and restore? I'm not looking forward to trying to get everything back and in the same place as before.
I can SSH into the phone if that makes any difference on what I can try.