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

### BEGIN /etc/grub.d/10_linux ###
menuentry "Gentoo GNU/Linux" --class gentoo --class gnu-linux --class gnu --class os {
        set gfxpayload=keep
        insmod ext2
        set root='(hd0,1)'
        search --no-floppy --fs-uuid --set ba16bd87-842c-46c2-a487-2a27d9be90dd
        echo    Loading Linux ...
        linux   /vmlinuz root=/dev/sda3 ro
}
menuentry "Gentoo GNU/Linux (recovery mode)" --class gentoo --class gnu-linux --class gnu --class os {
        set gfxpayload=keep
        insmod ext2
        set root='(hd0,1)'
        search --no-floppy --fs-uuid --set ba16bd87-842c-46c2-a487-2a27d9be90dd
        echo    Loading Linux ...
        linux   /vmlinuz root=/dev/sda3 ro single
}
menuentry "Gentoo GNU/Linux, previous kernel" --class gentoo --class gnu-linux --class gnu --class os {
        set gfxpayload=keep
        insmod ext2
        set root='(hd0,1)'
        search --no-floppy --fs-uuid --set ba16bd87-842c-46c2-a487-2a27d9be90dd
        echo    Loading Linux ...
        linux   /vmlinuz root=/dev/sda3 ro
}
menuentry "Gentoo GNU/Linux, previous kernel (recovery mode)" --class gentoo --class gnu-linux --class gnu --class os {
        set gfxpayload=keep
        insmod ext2
        set root='(hd0,1)'
        search --no-floppy --fs-uuid --set ba16bd87-842c-46c2-a487-2a27d9be90dd
        echo    Loading Linux ...
        linux   /vmlinuz root=/dev/sda3 ro single
}
### END /etc/grub.d/10_linux ###

cciss

### BEGIN /etc/grub.d/10_linux ###
menuentry 'Gentoo GNU/Linux' --class gentoo --class gnu-linux --class gnu --class os {
        load_video
        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 'Gentoo GNU/Linux (recovery mode)' --class gentoo --class gnu-linux --class gnu --class os {
        load_video
        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 'Gentoo GNU/Linux, previous kernel' --class gentoo --class gnu-linux --class gnu --class os {
        load_video
        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 'Gentoo GNU/Linux, previous kernel (recovery mode)' --class gentoo --class gnu-linux --class gnu --class os {
        load_video
        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
}
### END /etc/grub.d/10_linux ###

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/default/grub

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