Re: Bootloader produces garbage - reconstructing MBR
From: Alvin Oga (aoga_at_mail.Linux-Consulting.com)
Date: Sun, 3 Jul 2005 19:53:13 -0700 (PDT) To: Haines Brown <firstname.lastname@example.org>
On Sun, 3 Jul 2005, Haines Brown wrote:
> It happened that I could no longer mount my ide cdrom or my scsi cdrom
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
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.
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