Originally Posted by pyramid
The 30pin connector has been used since the birth of iPod, but what most user didn't realise is that its pins assignment was rearranged. Anyone recall that your docking, etc not able to charge newer iPod/IPhone? This is due to the charging current now being supplied through different pin (namely the USB assigned pin) instead of the orignally FireWire assigned pin within that 30pins connector. I'm not talking the actual FireWire or USB port, but the assigned I/O within 30pins connector. This rearrangement my looks just a simple swap, but you need to entirely redesign your electrical layout to do it properly.
It wasn't quite that simple. Apple didn't just say "Hey, charging will now occur on Pin Y rather than Pin X" to screw everyone over. The original 30-pin spec included a full set of FireWire pins AND a full set of USB pins built into the 30-pin spec, including the power pins for both, and all of the FireWire functionality was later removed to repurpose those pins for future uses (such as digital video out). Cloning the existing USB charging support over to the pin that used to supply FireWire current wouldn't have worked to maintain compatibility because a) that would have made for a redundant pin and thus reduced future expansion possibilities, and far more importantly b) FireWire supplies +12V current and USB is +5V.
The whole proprietary chip to get rid of the radio interference warning was indeed pretty lame though, but that warning was also removed in either iOS 4 or 5 regardless of whether the accessory in question had the authentication chip present.