Yesterday, we told you that Amazon's newest Kindles are shipping with locked bootloaders. We mentioned that this probably wouldn't prevent the devices from being rooted, as a method was already in the works. That method has now been confirmed, and root for the Kindle Fire HD is go!
Before you get started, you need to download SU:
After you download the file, extract the contents and pull SU from /system/bin/ and SuperUser.apk from /system/app/ and put them in the directory you'll be working from.
After that, execute the following commands:
rm -r /data/local/tmp
ln -s /data/ /data/local/tmp
echo 'ro.kernel.qemu=1' > /data/local.prop
adb shell mount -o remount,rw /system
adb push su /system/xbin/su
chown 0.0 /system/xbin/su
chmod 06755 /system/xbin/su
adb install Superuser.apk
After that, you should have root access. Congratulations!
If you happen to hit any snags along the way, head over to this support thread on RootzWiki.