Board Thread:News and Announcements/@comment-6252463-20130202013246/@comment-6252463-20130211230033

Aye, I'm pretty sure rooting it does void your warrenty. Fortunatly, from what I've read, it is extraordinarly difficult to brick the Kindle Fire compared to other Android devices. Also, I would make a backup using TWRP of the original Kindle ROM before flashing to a new version. With it, I can easily restore my Kindle to factory condition in just a few minutes.

In any case, even if my warrenty is voided, I get ten times more use out of my rooted kindle than I ever did with it in original condition, so I figure it's well worth it :)