Follow these steps to recover from a password expired root account:
- reboot system and boot from AIX CD/DVD #1
- once you get to the “main boot screen” of CD 1, don’t choose 1 to install, instead choose 3 (restore mode) afterwords, select to “mount the rootvg Volume group, and select option 1 to get to a shell”.
- export TERM=vt100, vi /etc/security/passwd, and delete the lastupdate under root: section