HD 8 cannot be downgraded. Will result in perma brick.
Just learned it the hard way. Tried to downgrade my Fire HD 8 (7th gen) v188.8.131.52 to the version 184.108.40.206 using the file "update-kindle-220.127.116.11_user_579225620.bin" and, as you said, hard bri...
Another success story here!
Just downgraded my in Dec. 2017 purchased Fire 7 (7th gen) from 18.104.22.168 directly to 22.214.171.124, using the image update-kindle-126.96.36.199_user_579225620.bin.
Everything went very smoothly. After the update, the first things...