I jailbroke my phones months ago but tonight it stopped working. So it would only turn on IF it was plugged in and even then it went to the apple logo for maybe 3 seconds then restarted. Then I held home when I restarted and tried to restore in itunes so now whenever I plug it in it always stays at the plug into the itunes thing, keep in mind ONLY turns on when plugged in. In itunes the phone Serial number isn't there and the name is"iPhone 5c." I run the restore and it the iPhone reboots then itunes gives me this, "The iPhone "iPhone" could not be restored. An unknown error occurred (21)"