Subject: Re: How to change serial baud rate on already installed bootblocks (netbsd-3-0-RELEASE)
To: Job Hanssen <job.hanssen@xs4all.nl>
From: David Laight <david@l8s.co.uk>
List: port-i386
Date: 09/06/2007 19:59:01
On Thu, Sep 06, 2007 at 09:03:02AM +0200, Job Hanssen wrote:
> 
> I'm not sure what you mean with pbr code.

The code that resides in sector zero of the partition, this is the code
that the mbr (sector zero of the disk) reads into memory and then execuctes.
> 
> Appearently there's no 'real' mbr at the moment:
...
> Partition table:
> 0: <UNUSED>
> 1: <UNUSED>
> 2: <UNUSED>
> 3: <UNUSED>
> 
> testbak# disklabel /dev/rwd0
> 
> - install a new mbr on /dev/rwd0d (using fdisk I suppose?). I suppose I 
> would feed it with the data from disklabel on partition c as input?
> - set the NetBSD-partition as active (also using fdisk)
> - (re)install the bootblock on /dev/rwd0a as already discussed in this 
> thread.

Sounds about right, except I'd install bootxx_ffsv1 into rwd0a first.
Running fdisk interactively will save you typing the sector numbers,
the partition type should be 169.

You also want to be careful of where the NetBSD disklabel is coming from.
On a disk without an mbr table it is probably coming from sector 1,
with a mbr table it would (normally) be read from sector 1 of the
netbsd mbr partition.
More recent kernels and disklabel(8) have got better 'hunt the disklabel'
code [1], but for 3.0 you might want to verify that both locations contain
the (same) disklabel, and once everthing is sane, delete the one from
sector 1 (NB always use 'raw' disk devices.)

	David

[1] All copies that can be found get updated to stay in sync.

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