FIX: iOS 8.3 & 8.2 iPhone rebooting or stuck on Apple / iTunes Logo - How To DFU Mode - YouTube
1. Make sure your iTunes is updated to the newest Version. If your iPhone was Jailbroken, you WILL have to use DFU mode to update to iOS 8 (or to reinstall 7.1.2 if you have an iPhone 4). DFU mode helps when your iPhone won't restore or is stuck on Apple ...