Re: Problems with grub2/initramfs-tools in chroot
On Friday 21 November 2014 22:43:11 Ross Boylan wrote:
> On Thu, Nov 20, 2014 at 9:11 PM, Scott Ferguson
>
> <scott.ferguson.debian.user@gmail.com> wrote:
> > On 21/11/14 15:13, Ross Boylan wrote:
> >> Over the last week I've repeatedly found my machine unbootable, in the
> >> sense I couldn't get to a working system without intervention.
> >> Sometimes I couldn't even get the grub2 menu.
> >
> > Tick
>
> I don't understand what you mean by tick.
You Americans! It's lucky that we English can talk American. Tick is the
English for check.
> [snip]
>
> >> Could changing the boot order in the BIOS change the drive mappings
> >> and screw up grub that way?
> >
> > Yes.
>
> Whichever drive I booted off of sda and sdb always referred to the
> same physical devices. And that was even though I booted into
> different operating system instances.
>
> But I guess the fact that linux can keep the names safe (via udev
> remembering serial numbers I suspect) doesn't really speak to the
> drive mappings that grub sees in its early operation.
>
> [snip]
>
> > I've had a 'similar' problem, in my case it was solved with:-
> > grub-install /dev/$Whatever
>
> I either executed that explicitly or, I assume, the grub package
> installation machinery did it for me. But I still had trouble.
>
> grub needs to know where it should jump to. I don't know how it can
> figure that out from inside a chroot. For example, say /boot inside
> the chroot is mounted from sdb2. To the chroot, it's just part of the
> filesystem. How is grub-install to figure out that, when it loads
> from the start of the disk, it should look for the grub directory (not
> /boot/grub) of the appropriate partition? The only possibility I can
> think of would be that it looks in /etc/fstab.
>
> > If the problem is GRUB, and you are actually booting from sdb (due to
> > the BIOS settings making it the boot device.
> >
> > Note: double check device names (you can use the GRUB device name) with
> > the mount command and use SMART to determine which device it the one set
> > to boot from in the BIOS.
> >
> >
> > Hope that helps.
> >
> >
> > Kind regards
>
> Thanks for your response.
> Ross
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