I've got this PowerMac 7300; nice old box. Problem is, I can't get it to
correctly sync on any of my VGA monitors. I've applied the System Disk
nvram patches
from the NetBSD FAQ, which work - but only for one reboot. If I reboot the
system a second time, the VGA monitor no longer syncs. I have a really old
Apple Color Display that will sync up every time, and if I disconnect that
after MacOS comes up, connecting the VGA monitor works.

Another strange thing, is that when I do get the VGA monitor to sync up at
the first reboot (after patching nvram with System disk), it goes blank
after about half way through the MacOS loading screen. I guess MacOS is
trying to set some strange resolution that it doesn't try to set if I have
the Color Display connected. I don't know, I know nothing about MacOS.

I'm sure I'm missing something obvious here.