new grub_boot_rescue hint

Daniel Armstrong daniel_armstrong at sympatico.ca
Fri Aug 3 00:17:06 PDT 2001


Hello, here is a hint I wrote up about using GRUB to make a boot and
rescue disk for my new LFS system. Maybe this might prove helpful to
other LFS users?

Take care...Daniel
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TITLE:		GRUB Boot & Rescue Disk - HOWTO
LFS Version:	All
AUTHOR:		Daniel Armstrong <daniel_armstrong at sympatico.ca>

SYNOPSIS:
	GRUB is the GRand Unified Bootloader, a boot loader program with many
cool features for the PC. It serves as a replacement for the more traditional
LILO. This hint shows how to use GRUB to make a combined boot loader and rescue 
disk for your LFS system.

HINT:
If you do not currently have GRUB installed on your system, you will need to 
download the most recent version (ftp://alpha.gnu.org/gnu/grub/grub-0.90.tar.gz)
and install it into your chosen working directory.

Now we unpack GRUB and install it on our system with the following commands:

tar xvzf grub-0.90.tar.gz
cd grub-0.90
./configure --prefix=/usr
make
make install

This will create the necessary executables and support files to create our boot
and rescue disk.

Grab a spare floppy and do a fresh format and install a filesystem:

fdformat /dev/fd0
mkfs -t ext2 /dev/fd0

Now we need to mount our soon-to-be GRUB disk:

mount -t ext2 /dev/fd0 /mnt

Create the directory and install the files GRUB will need to serve as your boot
loader:

mkdir -p /mnt/boot/grub
cp /usr/share/grub/i386-pc/stage1 /mnt/boot/grub
cp /usr/share/grub/i386-pc/stage2 /mnt/boot/grub

Now we are going to setup our GRUB floppy to do double-duty as a rescue disk 
for our LFS system, by placing a copy of the kernel on our floppy. This way if 
kernel on the hard drive is ever corrupted or trashed, we can use our GRUB boot
and rescue disk to get our system up and running again.

Copy your kernel to the GRUB floppy:

cp /boot/vmlinuz-2.4.7 /mnt/boot	#Your kernel and location may vary.

The final step before we reboot and test our GRUB boot and rescue disk is to 
install the GRUB tools in the Master Boot Record (MBR) of the floppy. Unmount 
the floppy but leave it in the drive:

umount /dev/fd0

Now type at the command prompt:

grub

This starts up the GRUB shell environment and changes your # prompt to "grub>".
Now enter:

root (fd0)
setup (fd0)
quit

Your GRUB boot and rescue disk is now complete. Leave the floppy in the drive 
and reboot. When the GRUB shell returns type:

root (fd0)
kernel /boot/vmlinuz-2.4.7 root=/dev/hda3	#Replace MY boot image and root
						#partition with your own
boot

Voila! Your LFS system should be up and running now.

For a more complete description of GRUB's many features, configuration, and 
installing GRUB on your hard drive's MBR, see the "Grub-HOWTO" hint at the 
LFS-Hints website and/or type "info grub" at your command prompt.

Thanks to Fabio Fracassi, the author of the "GRUB-Howto" hint, for getting me 
started with GRUB.

August 2, 2001 Daniel Armstrong <daniel_armstrong at sympatico.ca>


  

          


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