grub-install to a partition

[Barry Jackson]

I want to chainload into a system on sda21 from a dedicated grub2 on 
sda1 with :-

menuentry 'Mandriva 2010.1 x86-64' {
search --no-floppy --label --set 2010_1_64_root
chainloader +1
}

which works fine if the system on sda21 uses legacy grub.

I just installed grub2 to that system built from source (1.97~beta4) and 
with the bootloader in the MBR it boots fine, but after using :-

grub-setup --force --root-directory=/ /dev/sda21

...from within that system it fails to chainload from my dedicated grub 
partition.
All I see is "loading" then a black screen and it reboots.
/boot/grub/core.img and grub.cfg do exist.

I had difficulty stopping it jumping into a legacy stage1.5 which was 
embedded in the start of sda21 - I finally cured that with dd zeroing 
out the first 480 bytes of the partition.
grub-setup still fails to embed core.img though, but with --force it 
should still chainload IIUC.
I can boot the system directly with:-

menuentry 'Mandriva 2010.1 x86-64' {
linux (hd0,21)/boot/vmlinuz
initrd (hd0,21)/boot/initrd.img
}

...but that uses sdaxx device identifiers which I am trying to avoid in 
favour of labels.

Is there a later version that fixes this?

Thanks - Barry