I wanted to jailbreak my ATV2 so I can play my 720p MKV files through XBMC. I'm updated to the newest 4.2.2 firmware. It seems pretty easy to do an untethered jailbreak with Seas0npass. I'm looking for instructions on what to do right after the jailbreak. I wanted an easy step-by-step guide for installing a nightly build of XBMC (apparently the nightly version works best with 4.2.2 and 720p MKV files). Do I have to install the official version of XBMC first? If someone can post a guide here or link me to one that would be great!!