After some work today in my lab, I am afraid I have some disappointing news to report concerning password recovery with the Contivity 600. I have not finished yet, but it appears that the method I posted about earlier may not work. I still have several more code versions to try.
Having no experience with the method mentioned by Levendis, I decided to give it a shot. I did not actually clone the drive from another 600, I actually pulled one out of a 600 that had the default admin password and put it into one that I had changed the password on. Unfortunately, this did not work. I was not even able to factory default the box. I decided to call Nortel and get some information. I confirmed that the admin password is stored in the flash, and that the 600 must be RMA'd to Nortel if the admin password is lost.
I also confirmed something I found in the documentation for the 600: the FD button on the back is not enabled currently, but the RC button does boot the box into recovery mode.
So, to sum it up, if you've lost the password for your 600, there is nothing you can do but send the box back to Nortel.