So recently I was tasked with resurrecting a few old Sun machines from a closet. And of course once they were dug out, no one could remember the root or LOM passwords and the  since the machine was set to boot from the disk, I had no way in. But as they say, physical access trumps all. Here are the few steps I went through to gain access to the machine and re-install them.

Recover the ALOM password

Insert the installation disk and pull out the hard-drive.

Power-on the machine, this will eventually dump you to the ok> prompt where you can give it boot cdrom -s to get single user mode.

After the machine eventually boots you into single user mode, you can issue /usr/platform/`uname -i`/rsc/rscadm show/showuser to see the admin account.

Then /usr/platform/`uname -i`/rsc/rscadm userpassword <username> and enter the new password twice.

Boot from CDROM when boot order is set to boot from disk:

From the ALOM, issue poweron and then quickly issue console. This will start the machine and then switch you to the console terminal.

Once in the console terminal, give it a break command. I was able to do this with CTRL-BREAK on the keyboard.

This will dump you to the ok> prompt where you can then boot cdrom.