Specifications

iPhone 4 Troubleshooting — General Troubleshooting 33
2012-02-21
DFU Restore
Device Firmware Update (DFU) Restore allows you to perform a restore when all other attempts
to restore the device fail. DFU Restore is only necessary if:
• the device won’t turn on
• the device won’t go into recovery mode
• the device won’t charge
WARNING: This will delete all user data and settings on the device.
Procedure:
Timing is critical--use a watch to time the steps below!
1. Charge the device for at least 5 minutes, then connect to iTunes. If the device is not
detected, open iTunes and move to step 2.
2. Press Home + On/o buttons together and hold down for 8 seconds and then release the
On/o button.
3. Continue to press the Home button until you see the “Recovery Mode” message in iTunes,
which may take up to 30 seconds.
Note: In DFU Mode the device’s screen is blank.
If you did not get the “Recovery Mode” message in iTunes or the device’s screen is not blank/
black, repeat all steps paying careful attention to your timing.
If you decide not to do a restore, you may be able to escape by resetting the device.