Rebooting your iDevice
Hold down the Sleep (On-Off) and Home buttons totether for about 10-15 seconds or until the Apple Logo appears - ignore the red slider if it appears - then let go of the buttons. The iPad should begin to start up.
If this doesn't help then try restoring it:
Locked Out, Forgot Lock or Restrictions Passcode, or Need to Restore Your Device
8. RecBoot: Easy Way to Put iPhone into Recovery Mode - if all else fails.
Forgotten Restrictions Passcode Help
If this method does not work, then you will need to fully Restore your
device as New
This error is often related to USB timing. Try changing USB ports, using a different dock connector to USB cable, and other available USB troubleshooting steps (troubleshooting USB connections. If you are using a dock, bypass it and connect directly to the white Apple USB dock connector cable. If the issue persists on a known-good computer, the device may need service.
If the issue is not resolved by USB isolation troubleshooting, and another computer is not available, try these steps to resolve the issue:
- Connect the device to iTunes, confirm that the device is in Recovery Mode. If it's not in Recovery Mode, put it into Recovery Mode.
- Restore and wait for the error.
- When prompted, click OK.
- Close and reopen iTunes while the device remains connected.
- The device should now be recognized in Recovery Mode again.
- Try to restore again.
If the steps above do not resolve the issue, try restoring using a known-good USB cable, computer, and network connection.