On Sun, 4 Aug 2002, David Laight wrote:

> > > no, time for mbr(8):
> > >
> > >      3             No operating system.  The bootsector was loaded successful-
> > >                    ly, but it was not valid (i.e.  the magic number check
> > >                    failed).
> >
> > So maybe it's the offset thing. Short of rearranging the partitions,
> > maybe simply adjusting the values in the mbr (with "fdisk") could
> > trick the stage-1 loader into finding stage-2 at the right place.
>
> That error means that when the mbr code read what it thought was
> the first sector of the patition, the last two bytes were not
> 0xaa55 (or maybe 0x55aa).
>
> This means either:
> 1) you didn't write it there (/usr/mdec/installboot)

Or it wasn't written to the same place that the mbr code is reading
from. Noting that the start of the NetBSD mbr partition is actually
the swap partition, "wd0b", not the root partition, "wd0a", two
options present themselves:

a) Use "installboot -f" to write the second stage to "/dev/rwd0c" ==
"/etc/rwd0b". [But does the swap header leave room for bootblocks?]

b) Fudge the NetBSD mbr partition to point to "wd0a". If third-party
partitioning tools complain about gaps, put an entry for the swap in
mbr partition "4"; certainly nothing in NetBSD would care about that.

> 2) your BIOS doesn't support LBA addressing (so can't read any
>    sector above 8Mb).

Frederick