> > After the 'can't open boot' message the code does an 'int $0x18' bios call,
> > this was originally a call to execute the rom basic inetrpreter to to
> > a casette tape load (or similar), most systems go to a 'press a key to
> > restart the boot sequence'.
> 
> I've got a feeling it was wd1 - presumably if booting wd0 fails the BIOS
> tries wd1 instead before giving up.  Now I've got wd0 configured with
> proper boot code, I'll do the same for wd1.

A strong possibilty...

> > I've just commited a change to boot1.c that (should) make it possible
> > to boot straight from the raid set (ie without the 'boot' partition).
> > Use fdisk to put separate mbr partitions on the 'boot' and 'raid'
> > filesystems, and you can boot either with the bootselect code.
> 
> By this do I understand that wd{0,1}f with its copy of biosboot is
> unnecessary, and that copying biosboot to / on wd{0,1}a and re-issuing
> the /sbin/installboot command with rwd{0,1}a will "just work"?

With the new bootxx_xxxfs code yes.
The trick is managing to get the mbr partition to be aligned with wd0a
without losing the contents of the netbsd disklabel [1].
I THINK the following will work:
1) save the current label to a file
2) run fdisk to move the base of teh netbsd partition
3) rewrite the label from the file

Alternatively use dd(1) to copy the 2nd sector of wd0f to wd0a before
running fdsik to move the start point of the mbr sector.

Or just have 2 type 169 mbr partitions one covering wd0f and containing
the netbsd label and the other staring at the beginning of wd0a and
marked 'active'.

	David

[1] It is tempting to make the disklabel code write the label to all
netbsd partitions.  Also to put the code in (say) libutil (so sysinst
can call it directly) and remove the label writing code from the kernel.

-- 
David Laight: david@l8s.co.uk