I have a recent installation of Ubuntu 14.04.4 that is freezing at the "Loading initial ramdisk" stage of booting. What is the best way to troubleshoot this?

The hardware is a Lenovo Thinkpad e410, with an Intel i3 processor, Intel graphics, and a hardware-encrypted Samsung SSD. Ubuntu is installed under UEFI, and the kernel version is 4.2.0-35.

Everything was fine until a few days ago, except that graphics hardware acceleration was (sometimes? always?) not working correctly (images cutting into other windows, flashing blue, etc.). I eventually traced this to this bug and applied the fix suggested at #9, running "sudo update-initramfs -u -k all" afterwards. After the fix, the i915 driver did appear to load correctly, but it still did not appear to be working correctly. I then did two things: (1) updated the system, and (2) installed Flash for Firefox. Everything still appeared to be fine, with the exception of the graphics.

This morning, when I started my computer, the cursor was gone in Unity. I could still access the terminal, and decided to try undoing the above bug fix, running update-initramfs again afterwards. Rebooting, it froze at the urple screen. Rebooting via grub2's advanced menu, normal boot mode freezes at "Loading initial ramdisk." Recovery mode loads the ramdisk, then generates a few screens worth of errors including:

Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
...[5 lines + call traces omitted]...
---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
...[more lines + call traces omitted]...
---[ end trace ... ]---

And that's it. Results are the same if I try booting into 4.2.0-27, in both normal (freezes at "Loading initial ramdisk") and recovery (lots of kernel panic output, then freeze) modes.

I can try modifying grub boot options, but I'm not sure how to do this in grub2 or which options to try. Or I can try booting the live disk, mounting the hard drive, and poking around from there, but I don't really know where to begin.

Any suggestions very much appreciated.


I made the mistake of assuming all the background was part of the problem, when the problem was just that grub2 couldn't find the system:

Kernel panic - not syncing: VFS: Unable to mount root fs...

I imagine the cause is that I forgot to run "sudo update-grub2" after running "sudo update-initramfs."

The solution turned out to be to boot to a Live CD, mount and chroot to the hard drive, and re-run update-initramfs and update-grub2, as detailed here.

Two complications I encountered were:

  1. "fdisk -l" doesn't work on GPT volumes; you have to use "gdisk -l" instead.
  2. I have /boot and / on different volumes, and / is encrypted.

So I needed to modify the mount sequence as follows:

sudo cryptsetup luksOpen /dev/sdaX sdaX_crypt
sudo mount /dev/mapper/sdaX_crypt /mnt
sudo mount /dev/sdaY /mnt/boot
sudo mount --bind /dev /mnt/dev
sudo mount --bind /dev/pts /mnt/dev/pts
sudo mount --bind /proc /mnt/proc
sudo mount --bind /sys /mnt/sys
sudo chroot /mnt

So I am back into my system, though I still don't have a cursor. But that is another problem.


I'm not sure on the etiquette, but since this ranks high in a web search I figured I'd leave my solve for the issue here as well.

In my case the problem came about after using a USB flash drive (for storage, this is not my boot device) in xubuntu, then restarting and booting into windows, flash drive still in. After shutting down windows, I physically removed the flash drive.

Once I booted back to xbuntu I got a black screen. After trying to load an older kernel, I got the above mentioned “Loading initial ramdisk” freeze.

I fixed it by inserting the thumb drive into the same slot again, booting into windows, shutting down, then booting into xubuntu. I then unmounted the volume, removed it and restart without a problem.

Note that I was not able to boot into xubuntu simply by inserting the flash drive again, I had to boot into windows first.

Hopefully this helps someone out there.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.