Kernel update (64) will not boot. How can I automatically boot with earlier version? U12.04LTS

Ubuntu 12.04LTS

After an automatic kernel update through update-manager I cannot boot up without intervention any more. Latest version which GRUB boots automatically is 3.2.0-64-generic-pae which fails during startup at a blank screen.

[ 2.140928] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block (0,0)
[ 2.141024] Pid: 1, comm; swapper/0 Not tainted 3.2.0-64-generic-pae #97 Ubuntu

followed by a call trace, found at the end of the bootup in recovery mode.

It is not a disk error as I bootup properly with both 63 and 29.

May be the same as I want to recover my data on Ubuntu but maybe not. Others get the same message for unrelated (?) problems.

Another post has a reply which suggests it might be the boot cd - my cd has simcity in it - a wine project I am working on - getting it working !!

I am obliged to use 3.2.0-63-generic-pae in order to bootup properly.

How can I remove 64 and automatically bootup 63? I presume I have to edit a GRUB script but which and where is it?

If I physically remove 64 (how? which of the two shown below? do I need to make a new "generic" image?) will I then be deprived of future kernel updates which depend upon 64?

harveyp@harveyp:~$ sudo dpkg -l | grep linux-image
[sudo] password for harveyp:
ii linux-image-3.2.0-29-generic-pae 3.2.0-29.46 Linux kernel image for version 3.2.0 on 32 bit x86 SMP
ii linux-image-3.2.0-63-generic-pae 3.2.0-63.95 Linux kernel image for version 3.2.0 on 32 bit x86 SMP
ii linux-image-3.2.0-64-generic-pae 3.2.0-64.97 Linux kernel image for version 3.2.0 on 32 bit x86 SMP
ii linux-image-generic-pae 3.2.0.64.76 Generic Linux kernel image

Which kernel version to use ... has a reply which suggests ...

sudo apt-get purge linux-image-X linux-headers-X where X is the version that is giving you issues

but here too I am unsure what to do about the "generic" image as I have a pae 64 and a generic 64. And I don't wish to break it any more than it is already ...

Thank you for your help.

Solution 1:

To remove a new linux kernel version (for example linux-image-3.2.0-64-generic), use the following command:

sudo apt-get purge linux-image-3.2.0-64-generic linux-headers-3.2.0-64-generic linux-headers-3.2.0-64

This command will remove the kernel and associated headers and then update the GRUB boot loader. Subsequent boots will use the most recent previous kernel version on your system.

With kubuntu 12.04 and linux-image-3.2.0-64-generic I discovered that my windows applications would no longer run using crossover office. Hence I downgraded to 3.2.0-63.