first successful boot with GRUB floppy

Alan Lord lord_alan at
Wed Feb 1 00:43:30 PST 2006

Josh wrote:
  > One thing I noticed in doing this, was that my hard drives were swapped
> in grub, but not once the LFS Operating System took over.  What I mean
> by that is that where LFS's hda was grub's (hd0) and hdb was grub's
> (hd1), after I changed the boot priority in my BIOS, hda (the windows
> drive) was grub's (hd1) and hdb (linux) was (hd0) according to the grub
> rescue floppy disk.  Once I had booted LFS, however, my slave drive was
> still hdb and my original master drive was still (by process of
> elimination) hda.  I hope I didn't confuse anyone by saying that.

Hi Josh,

I didn't want to go into too much detail earlier but here goes:

You need to swap grub's understanding of the drives by using the file.

Get grub to build it then edit it and swap the hda/hdb lines around (so 
they point to hd1/hd0 respectively.

run grub and use the switch to use your edited file. When you 
run the root(...) and setup (...) commands, reference the swapped drive 
numbers (if you follow me). It is a bit scary at first but if you use 
the tab on the root command, you can see the partiton layout of the disk 
in question and it will confirm that grub thinks they have been switched.

You will also need to switch the drive references around in your 
menu.lst file. (You can also then try using the map command to swap 
drives and get grub to boot windows from hdb!!!)

Take your time and you should be fine!



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