8.4. GRUB-0.97

The GRUB package contains the GRand Unified Bootloader.

Approximate build time: 0.2 SBU
Required disk space: 10.2 MB

8.4.1. Installation of GRUB

Your shiny new LFS system is almost complete. One of the last things to do is to ensure that the system can be properly booted.



This package will only build for x86 and x86_64 architectures containing 32-bit libs. If you chose to build on x86_64 without 32-bit libraries (no multilib), then you must use LILO instead. Information on “boot loading” for other architectures should be available in the usual resource-specific locations for those architectures.

This package is known to have issues when its default optimization flags (including the -march and -mcpu options) are changed. If any environment variables that override default optimizations have been defined, such as CFLAGS and CXXFLAGS, unset them when building GRUB.

Start by applying the following patch to allow for better drive detection, fix some GCC 4.x issues, and provide better SATA support for some disk controllers:

patch -Np1 -i ../grub-0.97-disk_geometry-1.patch

By default, GRUB doesn't support ext2 filesystems with 256-byte inodes. Fix this by applying the following patch:

patch -Np1 -i ../grub-0.97-256byte_inode-1.patch

Prepare GRUB for compilation:

./configure --prefix=/usr

Compile the package, but use custom optimization flags to prevent an error flagged in the test routines:

make CFLAGS="-march=i486 -mtune=native -Os"

To test the results, issue:

make check

Install the package:

make install
mkdir -v /boot/grub
cp -v /usr/lib/grub/i386-pc/stage{1,2} /boot/grub

Replace i386-pc with whatever directory is appropriate for the hardware in use.

The i386-pc directory contains a number of *stage1_5 files, different ones for different file systems. Review the files available and copy the appropriate ones to the /boot/grub directory. Most users will copy the e2fs_stage1_5 and/or reiserfs_stage1_5 files.

8.4.2. Configuring GRUB

Boot loading can be a complex area, so a few cautionary words are in order. Be familiar with the current boot loader and any other operating systems present on the hard drive(s) that need to be bootable. Make sure that an emergency boot disk is ready to “rescue” the computer if the computer becomes unusable (un-bootable).

The procedure involves writing some special GRUB files to specific locations on the hard drive. We highly recommend creating a GRUB boot floppy diskette as a backup. Insert a blank floppy diskette and run the following commands:

dd if=/boot/grub/stage1 of=/dev/fd0 bs=512 count=1
dd if=/boot/grub/stage2 of=/dev/fd0 bs=512 seek=1

Remove the diskette and store it somewhere safe. Now, run the grub shell:


GRUB uses its own naming structure for drives and partitions in the form of (hdn,m), where n is the hard drive number and m is the partition number, both starting from zero. For example, partition hda1 is (hd0,0) to GRUB and hdb3 is (hd1,2). In contrast to Linux, GRUB does not consider CD-ROM drives to be hard drives. For example, if using a CD on hdb and a second hard drive on hdc, that second hard drive would still be (hd1).

Using the above information, determine the appropriate designator for the root partition (or boot partition, if a separate one is used). For the following example, it is assumed that the root (or separate boot) partition is hda4.

Tell GRUB where to search for its stage{1,2} files. The Tab key can be used everywhere to make GRUB show the alternatives:

root (hd0,3)


The following command will overwrite the current boot loader. Do not run the command if this is not desired, for example, if using a third party boot manager to manage the Master Boot Record (MBR). In this scenario, it would make more sense to install GRUB into the “boot sector” of the LFS partition. In this case, this next command would become setup (hd0,3).

Tell GRUB to install itself into the MBR of hda:

setup (hd0)

If all went well, GRUB will have reported finding its files in /boot/grub. That's all there is to it. Quit the grub shell:


Create a “menu list” file defining GRUB's boot menu:

cat > /boot/grub/menu.lst << "EOF"
# Begin /boot/grub/menu.lst

# By default boot the first menu entry.
default 0

# Allow 30 seconds before booting the default.
timeout 30

# Use prettier colors.
color green/black light-green/black

# The first entry is for LFS.
title LFS 6.5
root (hd0,3)
kernel /boot/lfskernel- root=/dev/hda4

Add an entry for the host distribution if desired. It might look like this:

cat >> /boot/grub/menu.lst << "EOF"
title Red Hat
root (hd0,2)
kernel /boot/kernel-2.6.5 root=/dev/hda3
initrd /boot/initrd-2.6.5

If dual-booting Windows, the following entry will allow booting it:

cat >> /boot/grub/menu.lst << "EOF"
title Windows
rootnoverify (hd0,0)
chainloader +1

If info grub does not provide all necessary material, additional information regarding GRUB is located on its website at: http://www.gnu.org/software/grub/.

The FHS stipulates that GRUB's menu.lst file should be symlinked to /etc/grub/menu.lst. To satisfy this requirement, issue the following command:

mkdir -v /etc/grub
ln -sv /boot/grub/menu.lst /etc/grub

8.4.3. Contents of GRUB

Installed programs: grub, grub-install, grub-md5-crypt, grub-set-default, grub-terminfo, and mbchk

Short Descriptions


The Grand Unified Bootloader's command shell


Installs GRUB on the given device


Encrypts a password in MD5 format


Sets the default boot entry for GRUB


Generates a terminfo command from a terminfo name; it can be employed if an unknown terminal is being used


Checks the format of a multi-boot kernel