Try and turn off iPod and proceed to step 3 of Recovery Mode.
1. Disconnect the USB cable from the device, but leave the other end of the cable connected to your computer's USB port.
2. Turn off the device: Press and hold the Sleep/Wake button for a few seconds until the red slider appears, then slide the slider. Wait for the device to turn off.
3.While pressing and holding the Home button, reconnect the USB cable to the device. The device should turn on.
4. Continue holding the Home button until you see the "Connect to iTunes" screen. When this screen appears, release the Home button. iTunes should alert you that it has detected a device in recovery mode. Click OK, and then click Restore to restore the device.
Note: Data will be lost. You may have to repeat the above many times.
This error occurs when the device unexpectedly loses its USB connection with iTunes. This can occur if the device is manually disconnected during the restore process. This issue can be resolved by performing USB troubleshooting, using a different USB dock-connector cable, trying another USB port, restoring on another computer, or by eliminating conflicts from third-party security software.
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. Also, discard the .ipsw file, open iTunes and attempt to download the update again. See the steps under Advanced Steps > Rename, move, or delete the iOS software file (.ipsw) below for file locations. If you do not want to remove the IPSW in the original user, try restoring in a new administrator user. If the issue remains, Eliminate third-party security software conflicts.