The Amazon Kindle Fire came out with a new firmware update, version 6.2.2. Right now, the only change that is obvious is that it brings the welcome feature of full-screen browsing. Unfortunately, it also breaks root for those who have rooted. Luckily, Justin Case also updated BurittoRoot to version 2 which fixes the rooting issue. This new version just needs adb and a few moments of your time to get you back into Kindle Fire customization heaven. Here's a breakdown of how it's done followed by a download link:

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 root

adb shell id

<if uid = 0 continue, if not start over>

adb remount

adb push su /system/xbin/su

adb shell chown 0.0 /system/xbin/su

adb shell chmod 06755 /system/xbin/su

adb remount

adb install Superuser.apk (skip this step if its already installed)
Download: BurritoRoot 2

Source: Kindle-FireForum.com via AndroidPolice and XDA