Whether it’s an unresponsive device, an upgrade gone bad, or some other sort of software-based gremlin, sometimes you literally have to force iTunes to recognize and restore your iOS device. Short for Device Firmware Update, DFU mode is a last resort for bringing misbehaving units back to working order—and here’s how to trigger it.
To start, you need to have the device plugged into your computer via USB, and then turn it off. Once it’s completely powered down, press and hold both the sleep/wake and Home buttons for ten seconds. After ten seconds, release the sleep/wake button but continue to hold the Home button down until you see a pop-up alert from iTunes telling you that it has “detected an iPhone/iPad/iPod touch in recovery mode,” and that it needs to restore the device before it can be used. If your device starts up normally without seeing this pop-up, simply try the process again—sometimes it takes a couple tries. And if that doesn’t work, well, there’s always the Genius Bar!