I have an iPhone 4 that is showing its age. It will charge when plugged into the wall charger. However, when I plug the same cable into a USB port on my computer it will not charge or be recognized at all by iTunes.
When I plug my new iPhone 4S into the same cable it is recognized and syncs just fine.
Is there anything I can try to get the iPhone 4 syncing via USB so I can update the OS and sync with iTunes, etc?
Edit: I will occasionally get the "This accessory is not optimized for this iPhone" message when I plug the iPhone into the cable connected to the USB port.