Really really odd one here...
Just bought a new stereo (Kenwood KDC-W6541U), which uses a dock connector via USB to plug in your iPod / iPhone.
If I plug my iPhone in, I can access all the files on there, and it says it's charging (although from my experience, it still seems to drain - which i'll come back to in a sec).
However after ~5-10 mins of playing music, it reboots. This happens continually...
If it's plugged in, but not being used for music - it never reboots (or at least not in the ~30 minute drives I've been testing it with).
I have no idea if there are any iPhone logs that could help me track down the problem.
The only idea I have is that apparently the pins (and voltage) to charge it up changed - which might explain why it doesn't charge. But not why it says it does - and then reboot!
Connection wise, it goes from the USB port on the HU, into an extension, into another extension & then to a dock cable. I was using the same dock cable with a USB charger, charging with no issues.
The iPhone is on 4.2.1 and Jailbroken with Greenpois0n.
Any ideas?