Hello mcantonioh,
Thanks for that info and for choosing the Apple Support Communities. If we understand correctly, you are unable to finish updating your Apple TV, as it is stuck on a blank white screen. First, disconnect Apple TV from the power outlet, wait five seconds, then reconnect it. Then see if you are able to start the Apple TV up normally and finish or do the update over: Restart Apple TV - Apple Support
If you are still having an issue, depending on what specific model you have, you maybe able to reset your Apple TV, or you may have to contact Apple directly for further assistance: Contact Apple Support
Cheers!