Hosed my MBR?

[Doug Poland]

On Mon, Apr 10, 2006 at 08:06:11PM -0400, Huy Ton That wrote:
> On 4/10/06, Doug Poland <doug at polands.org> wrote:
> >
> > Hello,
> >
> > I'm in a bit of a mess here.  I've got an Asus P4C800-E Deluxe
> > motherboard with two on-board SATA RAID controllers, an Intel MatrixRAID
> > (ICH5R) and Promise Fasttrak (PDC20378).  My BIOS allows me to boot
> > from either the Promise or the Intel controller.
> >
> > ...
> > 
> > The problem is, now, when I attempt to boot off the Intel controller, I
> > get a FreeBSD boot load failure:
> >
> > Invalid Partition
> > Invalid Partition
> >
> > So it would seem I hosed my MBR.  The question is, how did I do it and
> > how do I fix it?  I would think that when I choose to leave the MBR
> > untouched in sysinstall, that it would do just that.
> >
> > I cannot use the old DOS boot floppy trick of:  fdisk /MBR as DOS will
> > not recognize my Intel controller.  Windows installation media is
> > equally clueless.  I want to be very careful here so as not to render my
> > entire system useless.  A thought occurred to me that I might be able to
> > get a MBR from another Windows box
> >
> >    freesbie# dd if=/dev/ad0 of=/mnt/nfs/tmp/XP.mbr bs=512 count=79
> >    hosedbox# dd if=/mnt/nfs/tmp/XP.mbr of=/dev/ar1 bs=512 count=79
> >
> > and write that over my bad MBR.  Does that make sense?  Is there a
> > "better" way?
> >
>
> Boot off the WinXP disc & enter the repair utility (console).
> 
> You can type 'help' for all the commands.
> 
> There's a command called fixmbr; I think this is what you are looking for.
> 
Now this is getting OT, but recovery console doesn't show my drive.  How
do I know that it will fix the "correct" MBR?  Don't I have two MBR's?
one on each controller?

-- 
Regards,
Doug