dual booting debian gnu/linux and gnu/hurd

[aaric@posteo.net]

After installing Debian GNU/Linux:

I made a symbolic link to gnumach-1.8-486.gz from gnumach.gz.

I get this error:

Start ext2fs: ext2fs: device: (hostdisk//dev/sda,msdos1): No such device 
or address.

On the Hurd installation it has: set root='hd-49,msdos1'

My grub.cfg file has:

menuentry 'GNU/Hurd (on /dev/sda1)' --class hurd --class gnu --class os 
$menuentry_id_option 
'osprober-gnuhurd-/boot/gnumach.gz-false-cc99d437-43e3-4ac0-8cd7-dc3e385aa62b' 
{
    insmod part_msdos
    insmod ext2
    set root='hd0,msdos1'
    if [ x$feature_platform_search_hint = xy ]; then
      search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos1 
--hint-efi=hd0,msdos1 --hint-baremetal=ahci0,msdos1 
cc99d437-43e3-4ac0-8cd7-dc3e385aa62b
    else
      search --no-floppy --fs-uuid --set=root 
cc99d437-43e3-4ac0-8cd7-dc3e385aa62b
    fi
    multiboot /boot/gnumach.gz root=device:(hostdisk//dev/sda,msdos1)
    module /hurd/ext2fs.static ext2fs --readonly \
            --multiboot-command-line='${kernel-command-line}' \
            --host-priv-port='${host-port}' \
            --device-master-port='${device-port}' \
            --exec-server-task='${exec-task}' -T typed '${root}' \
            '$(task-create)' '$(task-resume)'
    module /lib/ld.so.1 exec /hurd/exec '$(exec-task=task-create)'
}