Arch Linux

theta

Member

From: India

Registered: 2010-01-16

Posts: 174

[Solved] - Root device not found - Unable to boot!

Before posting links to other threads or to the pacman/mkinitcpio wiki page please go through the following.
I know that many others are facing a similar problem, but I am posting this after spending 8+ hours (in 2 days) trying to get my system to boot.
And worst of all I don't have a working CDROM so I have to boot via an iso on a pendrive which is very frustating.

The exact message I get after the GRUB menu is:

ERROR: resume: hibernation device '/dev/sda3' not found
ERROR: Unable to find root device '/dev/disk/by-uuid/...'
You are being dropped to a recovery shell.
     Type exit to try and continue booting

Now I have already tried the following, by chrooting into my system:

1. As per the pacman wiki page, boot via live arch, chroot and run full upgrade. Then reinstall udev followed by mkinitcpio and then remake the image.

2. Downgrading to linux-3.3.4-2, udev-182-2x86-64 and mkinitcpio-0.8.8-1

3. Rearranging hooks in mkinitcpio.conf (usbinput before udev), and adding ext4 to MODULES array. Done this in both downgraded version and new kernel version (3.3.8-1)

After trying various permutations and combinations, I have failed and haven't been able to get past the first 8 lines after the grub menu.

An important point to note:
I had used the --force switch for 1 more package other than filesystem while updating which I don't remember now. I had to use it because some packages had gotten corrupted while downloading and I had to upgrade in parts. Also at no point during any of these trials did I get an error while rebuilding the initrd image.

If I remove the resume hook in /etc/mkinitcpio.conf then the first line "ERROR: ... " changes  saying that "no hibernation device specified".

Please suggest anything if you can!

Last edited by theta (2012-06-15 15:44:15)

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 20,643

Re: [Solved] - Root device not found - Unable to boot!

Do you know the partition that is supposed to be your root partition?
Grub cannot find it by its UUID.   Reboot, at the grub menu, highlight the kernel you want to boot, and press 'e'.  You are dropped into a simple editor which will allow you to change the boot command.  Replace references to /dev/disk/by-uuid/... with /dev/sdan, when n is the root partition number.

One other possibility.  Does your system have multiple drives?  Any chance the BIOS could be swapping them ?  (On second thought, that would not break UUID, But... it is something to be aware of using the technique I proposed)

If you do not know the partition arrangement, use that limited recover shell you mentioned to go look around and determine it.

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theta

Member

From: India

Registered: 2010-01-16

Posts: 174

Re: [Solved] - Root device not found - Unable to boot!

Do you know the partition that is supposed to be your root partition?
Grub cannot find it by its UUID.   Reboot, at the grub menu, highlight the kernel you want to boot, and press 'e'.  You are dropped into a simple editor which will allow you to change the boot command.  Replace references to /dev/disk/by-uuid/... with /dev/sdan, when n is the root partition number.

One other possibility.  Does your system have multiple drives?  Any chance the BIOS could be swapping them ?  (On second thought, that would not break UUID, But... it is something to be aware of using the technique I proposed)

If you do not know the partition arrangement, use that limited recover shell you mentioned to go look around and determine it.

Hmm, Thanks for this advice but I can't help saying that I'm not a noob .

Somehow the problem resolved itself with the new kernel update which came about half an hour ago (3.4.2-2). Suppose it will remain a mystery now!