Skip site navigation (1)Skip section navigation (2)
Date:      Mon, 10 Apr 2006 20:06:11 -0400
From:      "Huy Ton That" <huyslogic@gmail.com>
To:        "Doug Poland" <doug@polands.org>
Cc:        questions@freebsd.org
Subject:   Re: Hosed my MBR?
Message-ID:  <1cac28080604101706p6946cad6ka0649e3750494020@mail.gmail.com>
In-Reply-To: <20060410235508.GA742@polands.org>
References:  <20060410235508.GA742@polands.org>

next in thread | previous in thread | raw e-mail | index | archive | help
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.

On 4/10/06, Doug Poland <doug@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 PDC20378 runs two drives in a RAID0 configuration booting FreeBSD
> 6.0-STABLE.  The entire drive (ar0) is dedicated to FreeBSD and I have
> the boot-manager installed.   The ICH5R also runs two drives in a
> RAID0 for Windows XP.  I allocated roughly 25% of the drive (ar1) to
> Windows NTFS (ar1s1) and left the remaining disk open.
>
> Now that 6.x supports the ICH5R I decided to use the leftover disk (ar1)
> for a FreeBSD slice.  I used sysinstall's fdisk to create the slice in
> the unused portion of the disk.  I successfully committed the changes.  I
> then used # newfs /dev/ar1s2 to create a file-system and it went fine.
>
> The problem is, now, when I attempt to boot off the Intel controller, I
> get a FreeBSD boot load failure:
>
> ---
>
> Invalid Partition
> Invalid Partition
>
> No /boot/loader
>
> FreeBSD/i386 boot
> Default: 0:ad(0,a)/boot/kernel/kernel
> boot:
>
> Invalid partition
> No /boot/kernel/kernel
>
> FreeBSD/i386 boot
> Default: 0:ad(0,a)/boot/kernel/kernel
> boot:
>
> ---
>
> 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=3D/dev/ad0 of=3D/mnt/nfs/tmp/XP.mbr bs=3D512 count=3D7=
9
>    hosedbox# dd if=3D/mnt/nfs/tmp/XP.mbr of=3D/dev/ar1 bs=3D512 count=3D7=
9
>
> and write that over my bad MBR.  Does that make sense?  Is there a
> "better" way?
>
>
> --
> Regards,
> Doug
> _______________________________________________
> freebsd-questions@freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-questions
> To unsubscribe, send any mail to "
> freebsd-questions-unsubscribe@freebsd.org"
>



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?1cac28080604101706p6946cad6ka0649e3750494020>