Deepest type of restore you can do with your iOS device. The device is powered on, but has not yet booted up the operating system. When an iOS device encounters software or app-related trouble, it can usually be resolved by DFU mode.
DFU mode can be used in different situations including upgrading, downgrading or remove an expired beta version of the iOS.
Connect your iPhone or other iOS device to your computer and launch iTunes.
iPhone 6s or below – Power and home button
- Hold down both the power and home button.
- After 5 seconds, release the power button while continuing to hold down the home button. If the Apple logo appears, the home button was held down for too long.
- Nothing will be displayed on the screen when the device is in DFU mode. If open, iTunes will alert you that a device was detected in recovery mode. If your device shows a screen telling you to connect the device to iTunes, retry these steps.
iPhone 7 and up – Power and volume down
- Hold down both the power and volume down button.
- After 5 seconds, release the power button while continuing to hold down the volume down button. If the Apple logo appears, the home button was held down for too long.
- Nothing will be displayed on the screen when the device is in DFU mode. If open, iTunes will alert you that a device was detected in recovery mode. If your device shows a screen telling you to connect the device to iTunes, retry these steps.
Restore iOS software or hold option key and click restore to choose file.