Kernel Panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)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.
update-grub2