What is iPhone DFU mode? (Device Firmware Update)
iPhone DFU Mode is used to update the Firmware on your iPhone. It places your iPhone in a state where it does not load the operating system or bootloader.
How To Enter iPhone DFU Restore or Device Firmware Update Mode
- Connect the device into a computer running iTunes.
- Turn off the iPhone using the power button at the top of the iPhone.
- Hold the power and home buttons for 10 seconds, then while still holding the home button, let go of the power button and continue holding the home button until you see a mesage in iTunes telling you an iPhone in recovery mode has been discovered.
- While in DFU mode the iPhone screen will appear completly black. TheiPhone is not off, and is communication with the iTunes application.
- Do your Restore as propted by iTunes.
- If you change your mind, or otherwise need to exit DFU mode without changing your device, Hold down the home and power button on the iPhone until it restarts.
- You may need to quit and restart your iTunes application if your iPhone does not re-appear in iTunes.