Reinstalling GRUB after upgrade from Ubuntu 9 to Ubuntu 10.04

So I just upgraded my Ubuntu 9.10 desktop (well, EOL for longtime) to a more recent release, Ubuntu 10.04 LTS Lucid Lynx. So far the upgrade was pretty smooth except it took me like 3 hours to download and complete all the installation files.

Unfortunately it shows something like this after the reboot.

GRUB loading.
error: the symbol 'grub_puts' not found

grub rescue>

So I thought there is something going on with the GRUB during the upgrade, I grep a Ubuntu 10.04 Desktop iso (make sure it is Desktop iso instead of server iso, so that we could boot it up to Live CD mode. ) and boot it up to perform system rescue.

Once the Live CD is booted, I mounted / to somewhere under /mnt

/dev/sda1 on /mnt type ext4 (rw)

I tried chroot to /mnt and run grub-install from there, no dice.

root@ubuntu:/# grub-install  --force /dev/sda
/usr/sbin/grub-probe: error: cannot find a device for /boot/grub (is /dev mounted?).
No path or device is specified.
Try `/usr/sbin/grub-probe --help' for more information.
Auto-detection of a filesystem module failed.
Please specify the module with the option `--modules' explicitly.

So it is apparently the grub-installation on the disk is corrupted or something, I quited from chroot mode and simply run grub-install from the Live CD.

root@ubuntu:~# grub-install --root-directory=/mnt/ /dev/sda
Installation finished. No error reported.

After a reboot my machine is booting without any issue.