I am also having problems. I have an iPhone 4 and a U310BT. No problems with the Bluetooth connectivity, but the iPod function is very erratic. The unit recognizes the iPhone/iPod but frequently displays "Format Read" and will do nothing else. A regular iPod gets recognized and plays correctly. Only after multiple disconnects, source changes, and engine on/offs will the unit read the iPhone / iPod. Anyone have any suggestions, please? Thanks....