This is the procedure that I was given to use on C360s here at my daily saltmine for trusted systems that have been f***ed. If it has been set to secure mode then yank the hard disc, the boot will fail to the IODC where you can turn secure mode off. So far I haven't had to use it on the trusted systems, a word of warning though, the previous sys admin guru said that converting from trusted to standard MAY cause problems with some files. YOU HAVE BEEN WARNED!!!!
Power Up system, stop boot at IODC
At the IODC enter BOOT
At prompt interact with ISL? YES
Run HP-UX in single user mode hpux -is
Mount all volumes mount -a
Convert to standard security/etc/tsconvert -r
Edit password file /etc/passwd vi /etc/passwd
Clear root password (field 2)
Save changes :wq!
Set system level init 3
Log in as Root
Set Root password
Set system to trusted pwconv if necessary