Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Warning: Not compatible with iPhone 4 or 4S

We've tried an iPhone 3GS, 4, and now 4S with this adapter. We're using the official Apple USB charging cord.The 3GS will charge, but the 4 and 4S will not, complaining that the "accessory is not compatible". We've tried this in several cars and with several USB cords.