installboot killing disklabel?

[John Klos <john%ziaspace.com@localhost>]

I'm trying to use an amd64 system to install NetBSD/Alpha on a 120 gig 
SSD. Here's the disklabel:

16 partitions:
#        size    offset     fstype [fsize bsize cpg/sgs]
 a:   8388608         0     4.2BSD      0     0     0  # (Cyl. 0 - 8322*)
 b:   8388608   8388608       swap                     # (Cyl. 8322*- 16644*)
 d: 234441648         0     unused      0     0        # (Cyl. 0 - 232580)
 e: 217664432  16777216     4.2BSD      0     0     0  # (Cyl. 16644*- 232580)

I newfs'd /dev/sd0a as ffsv1, mounted, untargzipped the alpha sets, then 
copied usr/mdec/boot to the root of that filesystem, then 
usr/mdec/bootxx_ffs to the outside of that filesystem. I then unmounted 
and ran installboot:

installboot -vv -m alpha /dev/sd0d bootxx_ffs /boot

Checking the disklabel then shows:

4 partitions:
#        size    offset     fstype [fsize bsize cpg/sgs]
 a: 234441648         0     4.2BSD      0     0     0  # (Cyl. 0 - 232580)
 d: 234441648         0     unused      0     0        # (Cyl. 0 - 232580)

Why is installboot killing the disk's disklabel?

John Klos