To put an iPhone into Device Firmware Update mode, begin by opening iTunes on your computer and plugging the iPhone in. Hold the Home and Sleep/Wake buttons down at the same time for 10 seconds. Release only the Sleep/Wake button, and wait for iTunes to display a message stating that it has detected an iPhone in recovery mode.Continue Reading
Open iTunes on your Mac or Windows computer, and connect your iPhone to the computer using a USB cable.
Hold the Home and the Sleep/Wake buttons down simultaneously for 10 seconds until the screen goes completely black. If the Apple logo displays on the screen, start the process over.
After 10 seconds, release the Sleep/Wake button, and continue to hold the Home button for another 10 seconds until iTunes displays a pop-up stating that it has detected an iPhone in recovery mode.