Upon trying to upgrade from 10.10 to 11.04 all seemed to go well until the restart. This error message is what comes up:
Kernel Panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
How do we fix that?
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You are missing the initramfs for that kernel. Choose another kernel from the GRUB menu under Advanced options for Ubuntu and run
sudo update-initramfs -u -k version to generate the initrd for
version with the kernel version string such as
Start with a livecd, open a a terminal
sudo fdisk -l sudo mount /dev/sdax /mnt 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
and now you can make
update-initramfs and update-grub without errors.
update-initramfs -u -k 2.6.38-8-generic (or your version)
If you don't know your version. Use:
dpkg --list | grep linux-image
And just update Grub.
Reboot your system.
In my situation the problem was that
/boot was at 100% capacity, so the last 2 kernel updates had not completed successfully, hence on reboot when GRUB2 selected the latest Kernel, it failed.
I resolved the issue by booting into the oldest kernel installed, and removing some unused kernels using aptitude. By using aptitude, after the uninstall had happened, dpkg automatically tried to configure the broken packages, and this time succeeded.
In case this happened after an aborted kernel update (e.g. system crash while
dpkg --configure -a.
This will complete the upgrade, including configuring the boot settings as psusi explains.
The kernel boot messages tell you which disks you can use
For example, if in my test Linux 4.17 virtual machine setup I replace the correct
root=/dev/vdb the last message is:
---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)-
However, a few lines above, it shows messages of type:
VFS: Cannot open root device "vdb" or unknown-block(0,0): error -6 Please append a correct "root=" boot option; here are the available partitions: fe00 524288 vda driver: virtio_blk
which basically tells me straight out that
vdb was not found, but that there is a
/dev/vda which can be read due to the
virtio_blk driver (
In addition to Tomeu's instructions, before chroot I needed to:
sudo mount --bind /dev /mnt/dev
Additionally, after the chroot:
cp -r /usr/lib/i386-linux-gnu/pango /usr/lib/
You can also boot the server in rescue mode, and reinstall only the grub
I got this problem due to my /boot partition was full so my kernel updates had failed. I managed to fix this by booting from an old kernel in the GRUB menu.
When managed to boot I began purging old kernels, but I had manage to get some dependency issues so first I had to uninstall linux-server package
apt-get remove linux-server apt-get update apt-get -f install apt-get upgrade
Then I rebooted and everything was working fine!
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