boot-update -V

boot {
        generate grub
        default "Funtoo Linux genkernel"
        timeout 3
        scan /dev/sdc/boot
}

* WARN : invalid config setting "boot/scan"; ignored.

"Debian 1" {
        scan /mnt/debian/boot
        type linux
        kernel  vmlinuz[-v]
        initrd  initrd.img[-v]
        params += real_root=/dev/sdc2 nomodeset vga=791 ro
}

$ boot-update -V

 boot-update 1.5.2 / Copyright 2009-2011 Funtoo Technologies

 [use option "-l" for license info, "-h" for help]

 * Generating config for grub...

 * No /etc/fstab entry for /boot; not mounting.
 * Validating config file /boot/grub/grub.cfg
 * Backing up original config file to /boot/grub/grub.cfg.old
 * Writing new config file to /boot/grub/grub.cfg
 * Done.
           Debian 1 - vmlinuz-3.3.0-1.dmz.1-liquorix-amd64
           Debian 1 - vmlinuz-3.3-1.slh.2-aptosid-amd64
 DEFAULT > Funtoo Linux genkernel - kernel-genkernel-x86_64-3.3.1-gentoo
           Windows 7

 * Configuration file /boot/grub/grub.cfg generated - 40 lines.
 * Completed successfully.

set timeout=3

menuentry "Debian 1 - vmlinuz-3.3.0-1.dmz.1-liquorix-amd64" {
  insmod part_msdos
  insmod reiserfs
  set root=(hd2,2)
  search --no-floppy --fs-uuid --set 5475f7b7-ad03-4d3e-aee4-6801ee112fcc
  linux /mnt/debian/boot/vmlinuz-3.3.0-1.dmz.1-liquorix-amd64 real_root=/dev/sdc2 nomodeset vga=791 ro root=UUID=243fa9e0-4f6a-4dac-bd1c-a0742f78a9bc rootfstype=reiserfs
  initrd /mnt/debian/boot/initrd.img-3.3.0-1.dmz.1-liquorix-amd64
  set gfxpayload=keep
}

menuentry "Debian 1 - vmlinuz-3.3-1.slh.2-aptosid-amd64" {
  insmod part_msdos
  insmod reiserfs
  set root=(hd2,2)
  search --no-floppy --fs-uuid --set 5475f7b7-ad03-4d3e-aee4-6801ee112fcc
  linux /mnt/debian/boot/vmlinuz-3.3-1.slh.2-aptosid-amd64 real_root=/dev/sdc2 nomodeset vga=791 ro root=UUID=243fa9e0-4f6a-4dac-bd1c-a0742f78a9bc rootfstype=reiserfs
  initrd /mnt/debian/boot/initrd.img-3.3-1.slh.2-aptosid-amd64
  set gfxpayload=keep
}

menuentry "Funtoo Linux genkernel - kernel-genkernel-x86_64-3.3.1-gentoo" {
  insmod part_msdos
  insmod reiserfs
  set root=(hd0,1)
  search --no-floppy --fs-uuid --set 243fa9e0-4f6a-4dac-bd1c-a0742f78a9bc
  linux /boot/kernel-genkernel-x86_64-3.3.1-gentoo nomodeset vga=791 ro real_root=UUID=243fa9e0-4f6a-4dac-bd1c-a0742f78a9bc
  initrd /boot/initramfs-genkernel-x86_64-3.3.1-gentoo
  set gfxpayload=keep
}

menuentry "Windows 7" {
  insmod part_msdos
  insmod ntfs
  set root=(hd1,3)
  search --no-floppy --fs-uuid --set 12e4c634e4c619bd
  chainloader +4
}
set default=2

scan (hd2,2)/boot
scan /dev/sdc/boot
scan /dev/sdc2/boot
scan /dev/sdc2

gentoo-laptop ~ # eix -I grub
[i] sys-boot/grub
     Available versions:  1.98-r2 [M](~)1.99 {{+binfont custom-cflags debug mkfont static}}
     Installed versions:  1.98-r2(08:13:35 14.09.2011)(binfont -custom-cflags -debug -mkfont -static)
     Homepage:            http://www.gnu.org/software/grub/
     Description:         GNU GRUB 2 boot loader

gentoo-laptop ~ # uname -a
Linux gentoo-laptop 3.3.1-funtoo-r0a #1 Wed Apr 4 23:55:40 FET 2012 i686 Genuine Intel(R) CPU T1350 @ 1.86GHz GenuineIntel GNU/Linux

$ ls /mnt/gentoo/sbin/grub2*
/mnt/gentoo/sbin/grub2-install   /mnt/gentoo/sbin/grub2-mkdevicemap  /mnt/gentoo/sbin/grub2-probe   /mnt/gentoo/sbin/grub2-set-default
/mnt/gentoo/sbin/grub2-mkconfig  /mnt/gentoo/sbin/grub2-mknetdir     /mnt/gentoo/sbin/grub2-reboot  /mnt/gentoo/sbin/grub2-setup

grub2-mkconfig