Originally Posted by NiLuJe
K4 updates tend to do something funny with the shadow passwords, either resetting it from the one in diags or vice versa, can't ever remember which partition is what...
eval unset _dpinit && if mount | grep -q mmcblk0p2 ; then umount /dev/mmcblk0p2 ; fi && mkdir -p .b1 && mount -t ext3 /dev/mmcblk0p2 .b1 && cp /etc/shadow .b1/etc/shadow && sync && umount .b1 && rmdir .b1
On the K4s I bought from amazon one came with firmware 4.0.1 and password mario, but the next bought a couple of months later came with older 4.0.0 firmware with password fionaXXX. In both cases, the diags password was fionaXXX. When I bricked my 4.0.1 kindle, I recovered it by copying the firmware from my 4.0.0 kindle (including the shadow file with mario root pw). Doing upgrades did not change the password. As shipped both kindles had fionaXXX diags passwords.
Your script snippet above would explain the change from mario to fionaXXX (3 hex-digit DES password hash) described in this thread, but it did not seem to trigger when I applied the update to my kindles.
All of these posts about fionaXXXX (4 hex digits) default root passwords are not correct, not helpful, and only add to the confusion. You can verify that the root password is DES (with an 8 character limit) by inspecting the shadow file.
Of course if you CHANGE the root password to fionaXXXX (4 hex digits) then it gets a salted MD5 hash, and it is no longer a DEFAULT root password.
EDIT: It would be nice if the "kindle password" web page was corrected to not add to the "fionaXXXX confusion".