Can I un-jailbreak an Apple TV? – AppleTV 4 Jailbreak (appletv4jailbreak.com)
Yes, doing a restore, similar to how one does this on an iOS device, will reset it to the factory default settings and install.
You do this by going to Settings -> General -> Reset, and selecting restore.
If that doesnt work, you can also plug it into a computer with Micro USB, and use iTunes to restore.
More information is available in this Apple KB.
https://apple.stackexchange.com/questions/48020/can-i-un-jailbreak-an-apple-tv
AppleTV 4 Jailbreak (appletv4jailbreak.com)