[SOLVED] ERROR: Unable to find root device '/dev/sda3'

Question

Earlier I updated the kernel to my arch system and found this error while trying to boot. I hate to post this because there are so many topics like it, but I've been looking for hours for a solution to this problem and can't find one.
Here is the output:
Booting 'Arch Linux'
root (hd0,1)
Filesystem type is ext2fs, partition type 0x83
kernet /vmlinuz-linux root=/dev/sda3 ro
[Linux-bzImage, setup=0x4200, size=0x2ff2d0]
initrd /initrd @ 0xfd17000, 0x2c878c bytes]
Probing EDD (edd=off to disable)... ok
Decompressing Linux... Parsing ELF... done.
Booting the kernel.
:: Starting udevd...
done.
Waiting 10 seconds for device /dev/sda3 ...
ERROR: device '/dev/sda3' not found. skipping fsck.
ERROR: Unable to find root device '/dev/sda3'.
You are being dropped to a recovery shell
type 'exit' to try and continue booting
sh: can't access tty; job control turned off
My partition layout is like this:
swap: /dev/sda1
boot: /dev/sda2
root: /dev/sda3
extended: /dev/sda4
home: /dev/sda5
I have two hard drives, but i'm sure /dev/sda is the one with my OS.
Here are some things I've tried:
This was at the very bottom of the pacman wiki
# mkdir /mnt/arch
# mount /dev/sdaX /mnt/arch (your root partition)
# cd /mnt/arch
# mount -t proc proc proc/
# mount -t sysfs sys sys/
# mount -o bind /dev dev/
# mount /dev/sdaX boot/ (your /boot partition) #This step is not needed if you do not have a separate boot partition
# chroot .
# pacman -Syu udev mkinitcpio
# mkinitcpio -p linux
I've also tried performing the above, downgrading the kernel, updating my mirrorlist, reinstalling the kernel, and rebooting as mentioned here.
I've alsa tried a few other things that I've read, but can no longer remember.
Any help would be greatly appreciated! Thanks.
Last edited by colton7909 (2012-05-25 02:09:36)

Answer 1

Thank colton
Same problem here, but on a mac book (not mine eyh )
So, for those how have the problem (or need a live usb for mac or uefi systems),
1) with a 32bits system
- download gparted live cd
- use it for the step 3
2) with a 64bits system:
- you need the gparted live cd too: mount it and copy the EFI directory somewhere; then umount it;
- download a 64bits system (system rescue cd, as colton said is enough, follow the instructions for installation on their website first);
- mount you live usb, install the 64bits system;
- copy EFI system on the key
- edit the grub.cfg in EFI/boot/ , add the following before the other entries:
menuentry "System Rescue" {
set gfxpayload=keep
linux /syslinux/altker64 nomodeset efi
initrd /syslinux/initram.igz
3) repairing...
- boot the broken computer with the live usb
- mount the partition on which your system is (e.g. /dev/sda1 on /mnt)
- chroot it, init the system as needed (mount /dev, /proc, etc. the easier way is using init scripts)
% chroot /mnt /bin/bash
% /etc/rc.sysinit
% mkinitcpio -p linux