Rbox has released a pre-rooted version of the latest Fire TV 2 software update. You can get pre-rooted 18.104.22.168 here. You can install this new ROM regardles of what version is currently on your Fire TV 2. Be sure to also grab this MD5 file and include it with the ROM to ensure the ROM is not corrupted before flashing. A pre-rooted 22.214.171.124 ROM for the 1st-gen Fire TV, as well as a finalized fix for the TWRP looping issues for the Fire TV 1, will be released at a later date.