you havent been able to since kindle fire 2nd gen they have a boot lock on it making it impossible sorry
Boot lock meaning? mines rooted with a custom rom already But Cyanogenmod is better then what my buddy has up for
I havent been able to install rom's on my kindle fire 2 and mine's rooted but cyanogen is being worked on for kindle fire hd its not done yet from what i see but be patient
None work for kindle fire hd 7 reverand kyle is working on porting it to kindle fire hd Here's a video: