replace boot blocks on Soekris 4801

Hello, 

I didn't get any replies to my "manual upgrade" procedure, so I went ahead
and booted the 3.0 install kernel. sysinst did a pretty OK job, with a
couple of exceptions.  

I'm sure I said "use existing bootblocks" but I noticed a message that the
bootblocks were being replaced, and sure enough the boot(8) banner is
dated 2006.  That wouldn't be so bad except

	The new bootblocks don't work.  They don't boot any kernels -- generic,
install, 2.0 -- on my box.  

Fortunately, I have a second bootable device on that machine, a 128 MB
SanDisk.  I was able to use the boot utility on that drive to boot the 3.0
kernel.  All is well, mostly.  
Now, what to do?  Do I replace both /boot and the primary bootblock? 
Seems like I should, because that's the combination that booted the
machine.  Do I have to boot up in the 2.0 kernel to do that, or can I use
the 3.0 installboot(8)?  

Assuming I can do this from the machine as it's booted now (in 3.0), this
looks like the procedure:

1.  cp /BACKUP/boot /
2.  installboot -v -o timeout=5,console=com0,speed=9600 \
	/dev/rwd0a /BACKUP/usr/mdec/bootxx_ffsv1

Just checking on the filesystem.  Is this ffsv1?  

$ disklabel wd0 | grep a:    
 a:  58341024        63     4.2BSD   1024  8192 46600  # (Cyl.      0*- 
57878*)

Thanks for any advice.  

--jkl