I wanted to put a first generation iPod universal dock (model A1153) to use so I plugged it into the electrical outlet and used it to charge my iPhone 4 . The iPhone flashed this message: "This accessory is not optimized for this iPhone. You may experience noise caused by cellular interference and a decrease in cellular signal strength." The iPhone charged fine. Are there any problems with using this old dock with the iPhone? I won't be using it to sync data but just as a charger.