GNU GRUB Manual 2.12: Multi-boot manual config

Currently autogenerating config files for multi-boot environments depends on os-prober and has several shortcomings. Due to that it is disabled by default. It is advised to use the power of GRUB syntax and do it yourself. A possible configuration is detailed here, feel free to adjust to your needs.

First create a separate GRUB partition, big enough to hold GRUB. Some of the following entries show how to load OS installer images from this same partition, for that you obviously need to make the partition large enough to hold those images as well. Mount this partition on/mnt/boot and disable GRUB in all OSes and manually install self-compiled latest GRUB with:

In all the OSes install GRUB tools but disable installing GRUB in bootsector, so you’ll have menu.lst and grub.cfg available for use. Also disable os-prober use by setting:


menuentry "OS using grub2" {
   insmod xfs
   search --set=root --label OS1 --hint hd0,msdos8
   configfile /boot/grub/grub.cfg
}

menuentry "OS using grub2-legacy" {
   insmod ext2
   search --set=root --label OS2 --hint hd0,msdos6
   legacy_configfile /boot/grub/menu.lst
}

menuentry "Windows XP" {
   insmod ntfs
   search --set=root --label WINDOWS_XP --hint hd0,msdos1
   ntldr /ntldr
}

menuentry "Windows 7" {
   insmod ntfs
   search --set=root --label WINDOWS_7 --hint hd0,msdos2
   ntldr /bootmgr
}

menuentry "FreeBSD" {
          insmod zfs
          search --set=root --label freepool --hint hd0,msdos7
          kfreebsd /freebsd@/boot/kernel/kernel
          kfreebsd_module_elf /freebsd@/boot/kernel/opensolaris.ko
          kfreebsd_module_elf /freebsd@/boot/kernel/zfs.ko
          kfreebsd_module /freebsd@/boot/zfs/zpool.cache type=/boot/zfs/zpool.cache
          set kFreeBSD.vfs.root.mountfrom=zfs:freepool/freebsd
          set kFreeBSD.hw.psm.synaptics_support=1
}

menuentry "experimental GRUB" {
          search --set=root --label GRUB --hint hd0,msdos5
          multiboot /experimental/grub/i386-pc/core.img
}

menuentry "Fedora 16 installer" {
          search --set=root --label GRUB --hint hd0,msdos5
          linux /fedora/vmlinuz lang=en_US keymap=sg resolution=1280x800
          initrd /fedora/initrd.img
}

menuentry "Fedora rawhide installer" {
          search --set=root --label GRUB --hint hd0,msdos5
          linux /fedora/vmlinuz repo=ftp://mirror.switch.ch/mirror/fedora/linux/development/rawhide/x86_64 lang=en_US keymap=sg resolution=1280x800
          initrd /fedora/initrd.img
}

menuentry "Debian sid installer" {
          search --set=root --label GRUB --hint hd0,msdos5
          linux /debian/dists/sid/main/installer-amd64/current/images/hd-media/vmlinuz
          initrd /debian/dists/sid/main/installer-amd64/current/images/hd-media/initrd.gz
}

6.4 Multi-boot manual config