Kernel panic - Ubuntu refuses to start - What to do?

[Ed Cogburn]

Henrik Andersson wrote:

> sethmahoney wrote:
>> If you hit escape or enter or delete or something (I think it says while
>> its loading) while Grub is waiting to load, you can select which kernel
>> to use.  Load up using that kernel and then install a different kernel.
> 
> Ok, and how do I install a different kernel?
> 


The reason for the error message is that grub can't find your kernel boot
image, and that is most likely because a previous update to the kernel
image failed to correctly set the symlinks in /boot properly so they no
longer point to the right (or any) kernel image.  Alas, fixing this may
require the use of a boot CD, perhaps one of Ubuntu's CDs or something like
John Goerzen's (sp?) "Debian From Scratch" CD boot-image which is what I
keep around in case of emergency.  You'll need to boot into Linux from a
CD, mount your root system on the hard drive, then fix the reference.


> I certainly hope I will, but how can I prevent this from happening again?


If this happened because a kernel install failed to leave the symlinks in a
useful state, then always check that your lilo/grub is referring to an
existing file, or a symlink to an existing file, after you do one of those
updates.  Usually, grub is looking for /boot/vmlinuz and that file is a
symlink to the real kernel image which is in the same directory.  After an
update of the kernel just make sure that that symlink is still there and is
pointing to an actual kernel image.