GRUB

GRUB 2

Packages

Exherbo: sys-boot/grub

Gentoo: sys-boot/grub

Installation

# mount /boot

Install grub after mounting /boot.

# grub-mkconfig -o /boot/grub/grub.cfg

Standard installation:

# grub-install --recheck --no-floppy /dev/sda

HP Server /dev/cciss installation:

# grub-install --recheck --no-floppy /dev/cciss/c0d0

/sbin/grub-setup: warn: Your embedding area is unusually small. core.img won't fit in it.. /sbin/grub-setup: warn: Embedding is not possible. GRUB can only be installed in this setup by using blocklists. However, blocklists are UNRELIABLE and their use is discouraged.. /sbin/grub-setup: error: will not proceed with blocklists.

# grub-install --recheck --no-floppy /dev/cciss/c0d0 --force

/sbin/grub-setup: warn: Your embedding area is unusually small. core.img won't fit in it.. /sbin/grub-setup: warn: Embedding is not possible. GRUB can only be installed in this setup by using blocklists. However, blocklists are UNRELIABLE and their use is discouraged.. Installation finished. No error reported.

# umount /boot

Configuration

Standard

File: /etc/default/grub

GRUB_DEFAULT="GNU/Linux, current kernel"

File: /etc/grub.d/40_custom

#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
menuentry 'GNU/Linux, current kernel' --class gnu-linux --class gnu --class os {
        load_video 
        insmod gzio
        insmod part_msdos
        insmod ext2
        set root='(hd0,msdos1)'
        search --no-floppy --fs-uuid --set=root 5e056c75-61b4-42a5-8dd8-9fefd5f5b7fb
        echo    'Loading Linux ...' 
        linux   /vmlinuz root=/dev/sda3 ro init=/sbin/bootchartd
}
menuentry 'GNU/Linux, current kernel (recovery mode)' --class gnu-linux --class gnu --class os {
        load_video
        insmod gzio
        insmod part_msdos
        insmod ext2
        set root='(hd0,msdos1)' 
        search --no-floppy --fs-uuid --set=root 5e056c75-61b4-42a5-8dd8-9fefd5f5b7fb
        echo    'Loading Linux ...' 
        linux   /vmlinuz root=/dev/sda3 ro single
}
menuentry 'GNU/Linux, previous kernel' --class gnu-linux --class gnu --class os {
        load_video 
        insmod gzio
        insmod part_msdos
        insmod ext2
        set root='(hd0,msdos1)'
        search --no-floppy --fs-uuid --set=root 5e056c75-61b4-42a5-8dd8-9fefd5f5b7fb
        echo    'Loading Linux ...' 
        linux   /vmlinuz.old root=/dev/sda3 ro
}
menuentry 'GNU/Linux, previous kernel (recovery mode)' --class gnu-linux --class gnu --class os {
        load_video
        insmod gzio
        insmod part_msdos
        insmod ext2
        set root='(hd0,msdos1)'
        search --no-floppy --fs-uuid --set=root 5e056c75-61b4-42a5-8dd8-9fefd5f5b7fb
        echo    'Loading Linux ...'
        linux   /vmlinuz.old root=/dev/sda3 ro single
}

cciss

File: /etc/grub.d/40_custom

#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
menuentry 'GNU/Linux, current kernel' --class gnu-linux --class gnu --class os {
        load_video
        insmod gzio
        insmod part_msdos
        insmod ext2
        set root='(hd0,msdos1)'
        search --no-floppy --fs-uuid --set=root b3727853-ae78-4a00-b21c-7b974c233e1c
        echo    'Loading Linux ...'
        linux   /vmlinuzo root=/dev/cciss/c0d0p3 ro
}
menuentry 'GNU/Linux, current kernel (recovery mode)' --class gnu-linux --class gnu --class os {
        load_video
        insmod gzio
        insmod part_msdos
        insmod ext2
        set root='(hd0,msdos1)'
        search --no-floppy --fs-uuid --set=root b3727853-ae78-4a00-b21c-7b974c233e1c
        echo    'Loading Linux ...'
        linux   /vmlinuz root=/dev/cciss/c0d0p3 ro single
}
menuentry 'GNU/Linux, previous kernel' --class gnu-linux --class gnu --class os {
        load_video
        insmod gzio
        insmod part_msdos
        insmod ext2
        set root='(hd0,msdos1)'
        search --no-floppy --fs-uuid --set=root b3727853-ae78-4a00-b21c-7b974c233e1c
        echo    'Loading Linux ...'
        linux   /vmlinuz.old root=/dev/cciss/c0d0p3 ro
}
menuentry 'GNU/Linux, previous kernel (recovery mode)' --class gnu-linux --class gnu --class os {
        load_video
        insmod gzio
        insmod part_msdos
        insmod ext2
        set root='(hd0,msdos1)'
        search --no-floppy --fs-uuid --set=root b3727853-ae78-4a00-b21c-7b974c233e1c
        echo    'Loading Linux ...'
        linux   /vmlinuz.old root=/dev/cciss/c0d0p3 ro single
}

Updating Grub 2

# mount /boot

# grub-install --recheck --no-floppy /dev/sda

# umount /boot

Serial Console

Note: Manual grub2 configuration should always happen in /etc/default/grub

File: /etc/default/grub

GRUB_TERMINAL=serial
GRUB_SERIAL=COMMAND="serial --unit=0 --speed=57600 --word=8 --parity=no --stop=1"
GRUB_CMDLINE_LINUX_DEFAULT="console=tty0 console=ttyS0,57600"

Warning: Running the following command will overwrite any changes in grub.cfg you manually made

# mount /boot && grub-mkconfig -o /boot/grub/grub.cfg

If you want to be able to login to your system via the serial console you need to edit /etc/inittab.

File: /etc/inittab

Uncomment the s0 entry and change the speed to your needs.

# SERIAL CONSOLES
s0:12345:respawn:/sbin/agetty 57600 ttyS0 vt100
#s1:12345:respawn:/sbin/agetty 9600 ttyS1 vt100