If you don't want to use system disk, you can do what I did, 
which is to type blind the following:

  setenv output-device /chaos/control
  reset-all

Then you should be able to stumble your way through OF stuff.

-russ

Rich Noonan <macppc@fightgravity.com> writes:

> New user here.  Feel like I saw this discussed in a doc somewhere when I 
> started this project, but now I can't find it.  Apologies in advance if this 
> is covered...
> 
> System is a 7500 long ago upgraded with a 604 from a 9500.  Works fine under 
> OS9.  I applied the patch to System Disk, set to boot to OF, and hit save.  
> The system comes up and seems to sync video just fine, but I only get the 
> white screen.  No text, no prompt.  I have not attempted going over serial as 
> I'm anticipating needing X on this system and would prefer to get this sorted 
> out.  Any suggestions no what to try next?
> 
> Thanks-
> Rich Noonan