The Jtag hack was for the xbox 360 and it was named the JTag because it exploits the JTag port on the xbox 360. Anyone claiming to have a JTag hack for the xbox one is lying. There have been a few exploits for the Xbox One but none of them will do what you want to do. Here is a list of exploits:
https://wiki.xosft.dev/exploits/
If you want Homebrew you can activate dev mode so you don't need a hack. If you want piracy that's currently impossible and after watching the Platform Security Summit talk on the Xbox One I'm not sure it will be possible until we have Quantum computers that can break encryption or Microsoft massively fuck up a future update.