Comment 3 for bug 1103187

Last 6 hours I made quite a few experiments. The result is, that the first 1MB of the boot device and the /boot/ tree never changed, according to diff -q -r /boot/ ~/boot-reference/, and I used the command dd if=/dev/sda of=first-mega.bin bs=512 count=2048 to save the first MB.

The each of the dpkg-reconfigure grub-pc,

        dpkg -P grub-common grub-gfxpayload-lists grub-pc grub-pc-bin grub2-common
        rm -fr /boot/grub/
        apt-get install grub-pc

and grub-install /dev/sda ; update-grub attempts was enough for falling into grub rescue at next boot. Today I could never boot by hand at grub rescue prompt. However a simple boot with the Boot an existing Linux system installed on the disk menu item of the System-Rescue-CD 3.1.2 written on a pendrive, so a simple boot into the Ubuntu without any repair attempt was enough for successful reboots after this rescue boot. And surpisingly neither the first 1MB, nor the /boot/ tree changed.

One thing changed time to time, and I did not find any correlation with the destroy method, namely what kind of complain was above the grub rescue prompt:

Error: invalid arch-indepentdent ELF magic.

Error: symbol `g Glib-CR' not found.

Error: file `/boot/grub/i386-pc/normal.mod' not found.

Infinite many rows of: "not a correct XFS node", and then the usual normal mod not found message.

Each time the set at rescue promt gave the correct prefix and root information, and the ls was able the show the /boot/ tree. However, sometimes the item /boot/grub/i386-pc was told NOT a directory!

Regardless of these, today I was not able to load the /boot/grub/i386-pc/normal.mod with insmod, and the command linux and initrd was not available.