Re: grub-install to a partition

[Barry Jackson]

On 08/10/10 10:21, Jordan Uggla wrote:
> On Fri, Oct 8, 2010 at 1:29 AM, Barry Jackson<address@hidden>  wrote:
> > 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
> > }
>
> Loading grub's core.img via multiboot is more reliable than
> chainloading. For example:
>
> menuentry 'Mandriva 2010.1 x86-64' {
>    search --no-floppy --label --set 2010_1_64_root
>    multiboot /boot/grub/core.img
> }
Thanks Jordan,
Yes that works, however I see a snag in that Mandriva does not support 
grub2, so kernel updates will not automatically update core.img. On the 
other hand the links vmlinuz and initrd.img will be updated, so it would 
be better to use those.

> > 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
>
> Don't use grub-setup directly, use grub-install.
I tried grub-install --force first and chainloading still failed.
> > ...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
> > }
>
> This can be rewritten to use labels like this:
>
> menuentry 'Mandriva 2010.1 x86-64' {
>    search --no-floppy --label --set 2010_1_64_root
>    linux /boot/vmlinuz
>    initrd /boot/initrd.img
> }
Now this I like! :-)
Using this I see no reason to have any grub installed in the booted 
system at all. Just my grub2 dedicated partition booting the symlinks 
directly - clean and simple with no references to sdxxx or uuids which 
is what I was looking for - also no second menu gets displayed.

Many thanks for the tips,

Barry

> > ...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
> >
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