Trouble jumpstarting SPARCstation 10

I have a SPARCstation 10 I'm trying to clean off after decommissioning 
and install the latest OS that works there.  That would be Solaris 9 
Update 7 for sun4m.  This is the release that the machine was running.  
However, doing boot net of this same boot image panics the machine 
(trying to mount root?).  Same for Solaris 8 and 7.  CD booting Solaris 
7 doesn't panic (and presumably 8 and 9 wouldn't either, but as I'm 
preparing to divest of most of this Sun hardware, I don't have many SCSI 
CDROMs around (I have a Toshiba 3401, which is either 1X or 2X, and it 
can't find a bootblk on the Solaris 8, and cannot read the Solaris 9 
CD-R I found) and I don't know.  All of these netboot images work on my 
other two sun4m systems, a SPARCstation 5 and a SPARCstation 20.  The 
only odd thing I can think of about the 10 is that it has a PrestoServe 
DIMM in it.  Also, the 10's CPUs are 75MHz, and the 20s are 85MHz.

Has anyone run into this problem, and/or have a solution I haven't tried 
yet that works?

These three systems are very nearly available for the asking to Silicon 
Valley locals...

Jeff Woolsey