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Re: Bootloader produces garbage - reconstructing MBR

On Sun, 3 Jul 2005, Haines Brown wrote:

> It happened that I could no longer mount my ide cdrom or my scsi cdrom
> drives

that is a simple kernel option problem
	- fix lilo/grub config files
	- manually installt he modules manuall

> I can boot all three disks from a grub boot floppy, which I assume
> narrows things down to what's in the sda MBR rather than a hardware
> problem.

good.. says grub's MBR on the floppy is correct
> I copied (dd) the MBR on sda and sdc to img files. Being binary files,

how exactly was the dd command ??

	dd if=/dev/fd0 of=/dev/sda bs=448 count=1

	any other "dd" command is WRONG

	- NEVER copy binary files from xx to yy versions

> I could not get diff to tell me anything more than that they differed,

duh... why should it be the same

-- use the latest grub via cvs from gnu.org

> I need to do a MBR check, repair or restoration.
> To wipe the MBR clean, I read of doing # fdisk /MBR.

wipe it ( fdisk /mbr or dd if=/dev/null of=/dev/sda bs=448 count=1 )
and rerun lilo or grub

> Other than making the disk
> unbootable from its bootloader, which is already the case, are there
> any particular dangers doing this?

you dont need to worry.. you ahve a working boot floppy...
	save it as it.. forever

> I assume simply means doing >grub root and >grub setup.

grub-install /dev/sda
grub-install /des/db

c ya

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