[Nottingham] Boot stuck

Camilo Mesias camilo at mesias.co.uk
Mon Oct 20 16:29:42 UTC 2008

> What has gone wrong, and can I fix it with the Fedora rescue disk?

If it used to work once, but no longer works, what happened? Knowing
or guessing at how it's been broken could be a key to a quick fix.
Rarely a system update can change the order disks are discovered in
which might disturb the workings of grub. Adding or removing disks or
changing partition tables could have the same effect. The quick fix is
to edit the /boot/conf/grub.conf file to adjust the lines with (hdn,n)
in them - probably to (hd1,1) in your case.

Alternatively there are lots of instructions online for reinstalling
or fixing grub that would work, in the past I have done it from first
principles with a rescue disk, using mount, chroot then grub-install.
For some reason the command grub-install has a --root-directory option
but it didn't work for me, I had to use chroot. My Fedora setup had a
single partition mounted as /, and a smaller partition mounted as
/boot. The /etc/grub.conf is a soft link to a file in /boot so it has
to be mounted. The commands go something like this:

boot with rescue disk
mkdir /mnt/rootmnt
mount /dev/mapper/VolGroup00-LogVol00 /mnt/rootmnt
chroot /mnt/rootmnt
mount /dev/sdb1 /boot
grub-install /dev/sdb

Obviously the /dev/mapper and /dev/sdb1 will depend on your partition layout.

For safety have a good look around when you have finished mounting to
make sure everything looks right. If you have the wrong device then it
will either fail to mount or the filesystems will look wrong. If it
all looks right then grub-install should be a safe option - but it's
far better to find out what really went wrong rather than going in
guns blazing and reinstalling the lot.

Good luck!

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