Ajouter une entrée à grub

Bonjour,

Je souhaite à ajouter entrée dans grub pour pouvoir booter sur une autre
disribution (mandrake) située sur le hda6 (qui est monté en /mnt/z1 sous la
distribution kubuntu qui "détient" grub).

J'ai essayé :

title Partition essai
root (hd0,4)
kernel /vmlinuz root=/dev/hda6 ro console=tty0 quiet splash
initrd /initrd.img
savedefault
boot

mais grub me répond :
Erreur 15 : fivhier inexistant.

J'ai aussi essayé avec :
kernel /boot/vmlinuz root=/dev/hda6 ro console=tty0 quiet splash

Peut-être dois-je mettre /mnt/z1/boot/vmlinuz puis /mnt/z1/boot/initrd.img ?
Le root (hd0,4) est-il OK ?

Pour info, le lilo.conf créé par la mandrake contient :
image=/boot/vmlinuz
label="linux"
root=/dev/hda6
initrd=/boot/initrd.img
append="acpi=on resume=/dev/hda8 mem=1024M splash=silent"
vga=788
read-only

Et voici le menu.lst de grub à modifier (tout en bas)

# menu.lst - See: grub(8), info grub, update-grub(8)
# grub-install(8), grub-floppy(8),
# grub-md5-crypt, /usr/share/doc/grub
# and /usr/share/doc/grub-doc/.

## default num
# Set the default entry to the entry number NUM. Numbering starts from 0,
and
# the entry number 0 is the default if the command is not used.
#
# You can specify 'saved' instead of a number. In this case, the default
entry
# is the entry saved with the command 'savedefault'.
default 0

## timeout sec
# Set a timeout, in SEC seconds, before automatically booting the default
entry
# (normally the first entry defined).
timeout 10

## hiddenmenu
# Hides the menu by default (press ESC to see the menu)
#hiddenmenu

# Pretty colours
#color cyan/blue white/blue

## password ['--md5'] passwd
# If used in the first section of a menu file, disable all interactive
editing
# control (menu entry editor and command-line) and entries protected by the
# command 'lock'
# e.g. password topsecret
# password --md5 $1$gLhU0/$aW78kHK1QfV3P2b2znUoe/
# password topsecret

#
# examples
#
# title Windows 95/98/NT/2000
# root (hd0,0)
# makeactive
# chainloader +1
#
# title Linux
# root (hd0,1)
# kernel /vmlinuz root=/dev/hda2 ro
#

#
# Put static boot stanzas before and/or after AUTOMAGIC KERNEL LIST

### BEGIN AUTOMAGIC KERNELS LIST
## lines between the AUTOMAGIC KERNELS LIST markers will be modified
## by the debian update-grub script except for the default optons below

## DO NOT UNCOMMENT THEM, Just edit them to your needs

## ## Start Default Options ##
## default kernel options
## default kernel options for automagic boot options
## If you want special options for specifiv kernels use kopt_x_y_z
## where x.y.z is kernel version. Minor versions can be omitted.
## e.g. kopt=root=/dev/hda1 ro
# kopt=root=/dev/hda10 ro console=tty0

## default grub root device
## e.g. groot=(hd0,0)
# groot=(hd0,8)

## should update-grub create alternative automagic boot options
## e.g. alternative=true
## alternative=false
# alternative=true

## should update-grub lock alternative automagic boot options
## e.g. lockalternative=true
## lockalternative=false
# lockalternative=false

## altoption boot targets option
## multiple altoptions lines are allowed
## e.g. altoptions=(extra menu suffix) extra boot options
## altoptions=(recovery mode) single
# altoptions=(recovery mode) single

## nonaltoption boot targets option
## This option controls options to pass to only the
## primary kernel menu item.
## You can have ONLY one nonaltoptions line
# nonaltoptions=quiet splash

## controls how many kernels should be put into the menu.lst
## only counts the first occurence of a kernel, not the
## alternative kernel options
## e.g. howmany=all
## howmany=7
# howmany=all

## should update-grub create memtest86 boot option
## e.g. memtest86=true
## memtest86=false
# memtest86=true

## ## End Default Options ##

title Ubuntu, kernel 2.6.10-5-amd64-k8 Default
root (hd0,8)
kernel /vmlinuz root=/dev/hda10 ro console=tty0 quiet splash
initrd /initrd.img
savedefault
boot

title Ubuntu, kernel 2.6.10-5-amd64-k8 Default (recovery mode)
root (hd0,8)
kernel /vmlinuz root=/dev/hda10 ro console=tty0 single
initrd /initrd.img
savedefault
boot

title Ubuntu, kernel 2.6.10-5-amd64-k8
root (hd0,8)
kernel /vmlinuz-2.6.10-5-amd64-k8 root=/dev/hda10 ro console=tty0 quiet
splash
initrd /initrd.img-2.6.10-5-amd64-k8
savedefault
boot

title Ubuntu, kernel 2.6.10-5-amd64-k8 (recovery mode)
root (hd0,8)
kernel /vmlinuz-2.6.10-5-amd64-k8 root=/dev/hda10 ro console=tty0 single
initrd /initrd.img-2.6.10-5-amd64-k8
savedefault
boot

title Ubuntu, kernel memtest86+
root (hd0,8)
kernel /memtest86+.bin
savedefault
boot

### END DEBIAN AUTOMAGIC KERNELS LIST

# This is a divider, added to separate the menu items below from the Debian
# ones.
title Other operating systems:
root


# This entry automatically added by the Debian installer for a non-linux OS
# on /dev/hda1
title Windows NT/2000/XP
root (hd0,0)
savedefault
makeactive
chainloader +1

title Partition essai
root (hd0,4)
kernel /vmlinuz root=/dev/hda6 ro console=tty0 quiet splash
initrd /initrd.img
savedefault
boot

###############

Merci.

Olivier V