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...
Code:
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