I have 2 iPhone 3Gs: one suffered slight water damage and it stopped booting at all and even charging (after 24 hours to the wall). The other one, I bought off CL to discover later on that there is a annoying message that would keep popping up ” this accessory is not optimized for this iPhone” and “charging is not supported with this accessory” One night, I took both apart and switched the dock connectors (connection port) with one another and everything worked after that (except that the annoying message is now on the other phone). But now I know what part needs to be replaced. I hope this helps somebody cuz I lost countless hours of researching and trying to troubleshoot my iPhone problem. I was not able to find this suggestion anywhere on the web… worth mentioning that I tried all of the above suggestions and more also, the phone with the annoying message does not play sound while plugged in, so I really need to replace the dock connector assembly.