[arch-releng] grub install not listing partitions

Keshav P R the.ridikulus.rat at gmail.com
Fri Dec 16 10:25:07 EST 2011

On Fri, Dec 16, 2011 at 19:49, Eric Fernandez <zeb at zebulon.org.uk> wrote:

> 2011/12/16 Keshav P R <the.ridikulus.rat at gmail.com>:
> > I also want to point out the grub2 upstream does not recommend (but
> > supports) installing grub2 to a partition.
> But is that on a technical basis (like this fails 50% of the time) or
> just a warning: ok, the feature is there, but its support is not a
> priority. I never had any issue with grub on a partition, and if I
> chose to use it, I accept this is my responsibility.
It is due to the fact that installing to a partition involves storing the
sector/block lists of core.img in order to locate it. Since in many
filesystems the file sector locations change, this way of booting (using
sector/block lists of core.img) to locate the file may fail anytime.
Actually the same issue is with syslinux in which ldlinux.sys sector
locations should not change. Otherwise it will fail to boot. To ensure this
happens, syslinux sets the immutable attribute on ldlinux.sys but this flag
may not work with all the partitions. For more info read

> I don't whether the same applies
> > to grub-legacy. Syslinux by itself is simply installed to a partition
> with
> > a small code in the MBR which chainloads the syslinux partition. Syslinux
> > does not access files outside the partition in which it was instakked
> > (exceot maybe when chainloading using chain.c32), so ideally grub-legacy
> in
> > a partition can be replaced by syslinux (minus the MBR code). Users who
> > want a bootloader that can access (directly) files from multiple
> partitions
> > like grub-legacy does should go for grub2 as syslinux does not support
> that.
> >
> > Regards.
> >
> > Keshav
> The problem is that you cannot chainload syslinux from grub2, as far
> as I could read on forum discussions this year. So if I have grub2 in
> the MBR (and for some reason cannot change it), then syslinux is not
> useable.
> Eric

Yes, there seems to be some issue chaninloading syslinux from grub2. We
don't know where the issue is (grub2 or syslinux). But grub2 is so
feature-rich, if you have grub2 in the MBR, you do not need syslinux at all
(even if you are using multibooting across different discs with different
partitioning schemes).



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