I run a Sun Ray/VDI demo environment internally within the company - and because it's not a public service, I need to tell my Sun Rays to connect to it directly so that I don't get redirected to the corporate servers. To get any new Sun Ray to connect to *my* setup I usually pull out my laptop so that the Sun Ray can load the new version of the F/W along with the permission to pull up the management GUI via STOP-S.

But there is a better way if you have another Sun Ray server handy:

1) allow your Sun Ray to connect to the default corporate server
2) log in to a "regular" session, that is a Solaris or Linux desktop on the Sun Ray server itself
3) in a terminal, utswitch to your server (/opt/SUNWut/bin/utswitch -h myserver)
4) again, login to a regular session there
5) in a terminal,  issue "/opt/SUNWut/lib/utload -S myserver -w"
6) Watch your firmware load and wait
7) the Sun Ray will reboot and connect to the first server again. Repeat steps 2-4
8) issue "/opt/SUNWut/lib/utload -S myserver -f SunRay.enableGUI"
9) Press STOP-S and be merry

NOTE: I'm sure there is even yet a better way - this is totally unsupported, most likely a figment of my imagination. In any case, this post will self-destruct in BOOM.