I did a dumb thing... I forgot that Ubuntu 10.04 (Lucid Lynx) switched to GRUB 2 which puts a ton of *.mod files (kernel modules) in /boot/grub
. I thought they were soundtrack files put there erroneously, and I moved them. Needless to say, the next reboot was traumatic. I was presented with something I had no memory of ever seeing... a 'grub rescue>' prompt.
With the help of Fixing GRUB error: “error: unknown filesystem” however, I was able to recover...
- I discovered that GRUB rescue does not have 'cd', 'cp' or any other filesystem commands except its own variation of 'ls'.
So first I had to find the partition with the
/boot
directory containingvmlinuz
file and other boot image files... (approximation from memory of failed attempts, as well as blank lines for clarity, added 2014-07-10 by docsalvage)
grub rescue> ls
(hd0,4) (hd0,3) (hd0,2) (hd0,1)
grub rescue> ls (hd0,4)/boot
... some kind of 'not found' message
grub rescue> ls (hd0,3)/boot
... some kind of 'not found' message
grub rescue> ls (hd0,2)/boot
... grub ... initrd.img-2.6.32-33-generic ... vmlinuz-2.6.32-33-generic
I found a
/boot
directory containing thevmlinuz
filevmlinuz-2.6.32-33-generic
on partition(hd0,2)
.Then I manually booted from the 'grub rescue>' prompt. The following commands will...
- Set the
root
to use the/boot
directory on partition(hd0,2)
. - Load kernel module
linux
. - Set that module to use the kernel image
vmlinuz-2.6.32-33-generic
. - Set initrd(initialize RAM disk) to use the image
initrd.img-2.6.32-33-generic
. - Boot Linux.
- Set the
grub rescue> set root=(hd0,2)/boot
grub rescue> insmod linux
grub rescue> linux (hd0,2)/boot/vmlinuz-2.6.32-33-generic root=/dev/sda2
grub rescue> initrd (hd0,2)/boot/initrd.img-2.6.32-33-generic
grub rescue> boot
This boots and crashes to the BusyBox prompt which DOES have some rudimentary filesystem commands.
Then I moved the *.mod files back to the
/boot/grub
directory...
busybox> cd /boot
busybox> mv mod/* grub
busybox> reboot
The reboot was successful, but that was a lot of work.
Is there an easier way?