Justin Case has done it again, bringing root access back to users of Amazon's Kindle Fire who accepted the recent firmware update to version 6.2.2. BurritoRoot 2 is an easy-to-use exploit that only requires adb (Android debug bridge) and a few moments of your time. Users looking to root their device after Amazon's latest firmware update can grab BurritoRoot 2 using the download mirrors below.
To use the exploit, just download the file and run the following commands from adb:
adb push BurritoRoot2.bin /data/local/
adb shell chmod 777 /data/local/BurritoRoot2.bin
adb shell /data/local/BurritoRoot2.bin
adb shell id
<if uid = 0 continue, if not start over>
adb push su /system/xbin/su
adb shell chown 0.0 /system/xbin/su
adb shell chmod 06755 /system/xbin/su
adb install Superuser.apk (skip this step if its already installed)
For more information, check out Justin's original thread over at XDA.