Put your iPod Touch in DFU mode, restore and update it with iTunes.
- Connect the iPhone to your computer and launch iTunes
- Turn the iPhone off (hold down the power button at the top of the iPhone)
- Hold down the sleep/power button and home button together for exactly 10 seconds, then release the power button
- Continue to hold down the Home button until a message appears in iTunes telling you an iPhone in recover mode has been detected
- When you are in DFU mode your iPhone screen will be completely black
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.
Follow the steps listed above for Error 1604. This error may also be resolved by disabling, deactivating, or uninstalling third-party security, antivirus, and firewall software. See steps in this article for details on troubleshooting security software.