Ok here is my situation. My Iphone 3g was dropped in water. It is unlocked/jailbroken. It will not turn on at all with the power button. When I plug it in and Itunes opens it says it is in recovery mode and needs to be recovered to get out. Everytime I try to recover even with custom IPSW's I get the same Error (21). Also the 3rd ribbon cable is disconnected inside the phone but this should not be causing it because that is for the earpiece. After I try the recovery though sometimes the screen will turn white and stay that way until I hold the power button or try to recover again. I'm not sure how to fix this, if I got it working I was going to repair the 3rd ribbon but if there isn't a way then I dont see the point.