In message <20040521201142.GW7278@snowdrop.l8s.co.uk>, David Laight writes:
>> 
>> Ah -- that seems to be the problem.
>> 
>> 1: NetBSD (sysid 169)
>>     bootmenu: NetBSD
>>     start 21546000, size 56594160 (27634 MB, Cyls 1425-5168)
>> 
>>  a:    567000  21549780     4.2BSD   1024  8192 40504  # (Cyl.  21378*-  219
>41*)
>> 
>> 
>> Now to figure out how best to fix it...
>
>installboot to whatever is at the start.
>(or dd bootxx_ffsv1 aroung the netbsd label)
>the system will look for /boot there, then fall back onto 'a'

The problem is that for some reason, I have the fdisk partition 
starting earlier on the disk.  I'm contemplating just running fdisk and 
changing the start point of that partition -- the amount of storage 
involved is small compared to the size of the disk.  But -- do fdisk 
or disklabel round things to any boundaries?  I'm trying to understand 
how the problem happened in the first place.  (Hmm -- there are 3780 
unused sectors between the start of the mbr partition and the start of 
the NetBSD partition.  What would happen if I made wd0h point to that 
sliver, and copied /boot there?  Would it know to look in the 'a' 
partition for /netbsd?)

		--Steve Bellovin, http://www.research.att.com/~smb