Re: boot issues: Grub? on 12.04 LVM w/ disk encryption
A new /boot/initrd.img is installed with every new kernel. In an encrypted installation it has the job of decrypting the / file system so the kernel can mount it at at boot time.
If your initrd.img file is corrupted or incomplete or is failing to decrypt you / partition for some reason then that could be the cause of your error message: alert: /dev/mapper/xxx doesn't exist. (Because as far as the kernel is concerned, it doesn't exist, since it cannot read it to find the files in /etc/init, which it needs to continue booting).
It's relatively easy to make a new initrd.img with the mkinitramfs command, man mkinitramfs
If you want to use a GUI method you can probably use synaptic packager to uninstall the suspected faulty kernel and initrd.img. Just install synaptic if you don't already have it. Then open synaptic Package Manager and do a search for linux-image. You should be able to completely remove it as long as it's not the one you have booted at the moment and try installing it again.
Last edited by Herman; February 10th, 2014 at 07:33 AM.
Ubuntu user since 2004 (Warty Warthog)