In order to restore or update your apple device from an ipsw backup file you simply perform the following steps, be sure to have your ipsw backup file on the computer that you are restoring from, that your device is connected, and your iTunes is up to date.
- Open iTunes,
- Click on the connected device under "Devices"
- On PC; Hold the Shift key and click the "Restore" or "Update" button,
- On Mac; Hold the Option key and click the "Restore" or "Update" button,
- Follow on screen prompts.
John "Mike" Wright