[arch-general] Can't boot, root device not found

[FGr]

Excerpt from Josh Silard's message
of 2012-03-18T23:58-0400:

> Hi list,
> 
> I recently performed an update of udev and my kernel and after this
> I am unable to boot the normal kernel or the fallback. When I try I
> get this error:
> 
> ERROR: Unable to find root device
> '/dev/disk/by-uid/03619a2f-908f-4724-ba4b-1fb3985e382b'
> You are being dropped to a recovery shell
> Type 'exit' to try and continue booting
> sh: can't access tty; job control turned off
> 
> Typing exit results in me dropping to another shell and if done
> repeatedly a kernel panic. I attempted to boot via the grub console
> using the sda device block but I came up with the same error. When
> I look in /dev through the recovery console that comes up the sda*
> blocks aren't present.
> 
> I need to know if there is a way to do this without entirely
> reformatting my system, I also don't have easy access to another
> computer but I have an android phone. Any assistance is greatly
> appreciated.

You can try SystemRescueCd to boot the computer, then type the
following:

mkdir /mnt/lx
mount /dev/sda1 /mnt/lx
mount -o bind /proc /mnt/lx/proc
mount -o bind /dev /mnt/lx/dev
mount -o bind /sys /mnt/lx/sys
chroot /mnt/lx/ /bin/zsh
grub-install /dev/sda [--recheck]
exit
umount /mnt/lx/dev
umount /mnt/lx/proc
umount /mnt/lx/sys
umount /mnt/lx/boot
umount /mnt/lx