On Sat, May 12, 2007 at 12:03:24AM +0200, Zbigniew Baniewski wrote:
> 
> Partition table:
> 0: NetBSD (sysid 169)
>     start 63, size 12692673 (6198 MB, Cyls 0-790/22/1), Active

This fdisk partition starts at the same sector as the BSD disklabel
partition wd0a.

> debian# disklabel /dev/wd0
> 
> 5 partitions:
 ^^^
 ^^^ Notice how you have only three partitions listed below?  But there
     are actually two more, of type "unused" -- so disklabel does not
     print them out for you by default.

What's going on is that somehow you got an unused wd0e partition in your
disklabel whose first sector matches that of wd0a (perhaps by using
mbrlabel -- it defaults to partition 'e' for the first MBR partition).
Now that that's there, the bootblock can't tell which one you actually
want to boot from.

The solution is to edit the disklabel and change the "5 partitions" line
to "4 partitions" (4, not 3, since you don't want to lose partition 'd'
which should be unused and which is the whole disk).  Then all will work
as you expect.

Thor