All fdisk /mbr does is replace your mbr with windows info...the most it would screw up is grub / lilo (what ever is in your mbr). That can be replaced with any livecd and a quick command from grub or lilo. -----Original Message----- From: Gregory Avedissian [mailto:gma2004@verizon.net] Sent: Sunday, July 25, 2004 11:43 AM To: douglas.waud@umassmed.edu; Worcester Linux Users Group Subject: Re: [Wlug] Partition table blues Hi Doug, I haven't tried fdisk /mbr because I don't really fully understand what it does and have never seen a good explanation of how it will affect linux partitions. This morning, I read that it shouldn't be used on disks that have more than four partitions. I have five partitions and some unclaimed space. I might try it later today. Beside that, anything of value is on the linux side of the disk. (That's not a microsoft slur, it's just where I have my files.) So, while I would like to be able to get the whole thing back to its original working order as a learning exercise, I'm more motivated to get to the linux partitions. Thanks again, Greg doug waud wrote:

Hi again

This time, let's try focussing on one thing to try.

I don't see that you have ever tried the standard way to restore the MBR for Windows --- boot a Windows floppy with fdisk on it and type fdisk /mbr and, if you still cannot boot windows, add a sys c:

It is not clear from here why you did not try this.

doug

Gregory Avedissian wrote:

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doug waud wrote:

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Hi again Greg

Gregory Avedissian wrote:

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There were three backups of the mbr. One made under dos with debug.exe, and the others made with linux as,

dd if=/dev/hda of=/boot/boot.MBR bs=512 count=1 dd if=/dev/hda of=/boot/boot.446.MBR bs=446 count=1

I restored with:

dd if=/boot/boot.MBR of=/dev/hda bs=512 count=1 I think maybe I picked the wrong one.

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I admit I would have used the second, safer (since it does not touch the partition table), but I don't see why the 512 bs variant would not have worked unless you had changed the partition table since making that boot.MBR file.

No, I didn't change the partition table. I made these backups within days of installing, so that I would have copies of a new, working mbr.

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It is hard to tell what went wrong until you tell us what you were doing just before the system no longer would boot. (Those two lines creating the boot.xyz files would only read from the first 512 or 446 bytes not do any writing there so they cannot be the cause of your troubles.)

Why don't you boot from a bootable floppy? Alternatively, start the SuSE recovery mechanism which includes "boot an installed system" as an option. If all that is screwed up it the MBR, you could then simply run LILO to refresh it.

I had a new win98 installation working ok, then I installed suse8.2 and set it up so that it would boot with GRUB from floppy. I don't recall if I ever tried to boot from the harddrive to get into windows after I installed suse, but I know I could get there from the floppy.

When I did try to boot off the hard drive two days ago, it hung with the message, "Disk boot failure. Insert system disk."

I could still boot to win or linux from the grub floppy at this point. I tried restoring the mbr in dos with debug.exe, and that didn't help. I could still boot to linux with the floppy, and I can't remember if I could still boot to windows. Then I tried restoring with dd if=/boot/boot.MBR of=/dev/hda bs=512 count=1

After that, I couldn't boot from the grub floppy anymore. Trying to boot the installed system from the rescue disk also failed. I then booted to the rescue system. Output of sfdisk -l looked like this:

Disk /dev/hda: 3737 cylinders, 255 heads, 63 sectors/track /dev/hda: unrecognized partition No partitions found

Repeating the restore procedure with debug.exe didn't help, either.

Thanks, Greg

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