Option #1 - though I don't use this to know how stable:
1) Set the boot code host=MyHostName -- I believe this is in TCL6 as well as older models
If you have opt=(persistent) as a boot code (preferred), you can easily do the following:
1) Create a file /opt/hostname (and inside it, enter your hostname on a single line)
2) Edit /opt/bootsync.sh and replace sethostname box to sethostname `cat /opt/hostname`
If you must rely on "backups" you can
1) Create a file /opt/hostname (and inside it, enter your hostname on a single line)
2) Edit /opt/bootsync.sh and replace sethostname box to sethostname `cat /opt/hostname`
3) Edit /opt/.filetool.lst and make sure opt is listed
4) Run filetool.sh -b as non-root
*) As long as the boot code norestore IS NOT being used, this should work flawlessly
A final desperate method would be to edit (and back up) /opt/bootlocal.sh and add the line:
sethostname hostname &
This applies a little AFTER boot, so it may be invisible to you initially.
Which ever direction you take, when it's finished simply type in hostname at the prompt (or from Terminal if using a desktop) to make sure it "took."
Good luck!