: Return to iTunes, hold the Shift key (Windows), click Restore , and select your custom firmware file.
[F.A.Q.] iREB 4.0.x-4.1-RC2. Как обойти ошибки 16xx ... - UiP iREB 4.0.x 4.1 RC2.zip 1
Follow the on-screen instructions to put the device into DFU mode. iREB then applies the exploit to "pwn" the device. : Return to iTunes, hold the Shift key
Usually related to USB communication or Apple’s security checks blocking the restore process. : Return to iTunes