How do i restore my iPhone 3GS that is in a pwned dfu state. It does not boot up at all and is no longer recognized by itunes. It still works because when plugging it in, my computer recognizes it but it does not show up on itunes? I was trying to restore it before all of this when it was just in DFU mode but after using iReb, the phone does not boot up and is always on a black/blank screen