How to update / restore your Apple TV using the downloaded IPSW file:
1. Download the firmware to your hard drive
2. Connect your device to your Mac or PC using the connection cable
2. On Macs OPTION-click and on PCs SHIFT-click the Update / Restore button on the Apple TV screen in iTunes
3. Select the IPSW file you downloaded to update / restore your device
4. Wait for the Apple TV to finish the update / restore process
It is highly recommended to always use the most recent driver version available.
Try to set a system restore point before installing a device driver. This will help if you installed an incorrect or mismatched driver. Problems can arise when your hardware device is too old or not supported any longer.