2012-01-14, 09:07 PM
Just relating my experiences...
I recently build a Ubuntu 10.10 box (logan) from a unetbootin image (boot from USB pen), then used apt-get to install apps I was missing as well as updating current packages to their newer counterparts, but came across something interesting: one of my other boxes (neptune), updated to the hilt, had kernel version 2.6.35-31-generic... however after an "apt-get update" and "apt-get upgrade" to bring all the packages up to their latest, logan was still on 2.6.35-22. Weird.
I could run "apt-get install linux-headers-2.6.35-31" (and also linux-headers-2.6.35-31-generic) which would bring the newer kernel down, but after a reboot I was still on 2.6.35-22.
Eventually I fathomed out the issue, which required two things to be done:
<ol style="list-style-type: decimal">
[*]Install linux-image-2.6.35-31-generic
[*]Run "update-grub".
</ol>
The second command rebuilds your grub.cfg, but the "10_linux" script which adds kernel images to the boot loader only finds them if the "linux-image" package is installed, so consequently any manually-installed kernels were being overlooked previously.
Once I'd put the right package in place (the install of which re-ran "update-grub" automatically) a reboot showed the newer kernel in use, and the older ones could be cleared out with "apt-get remove linux-headers-2.6.35-22" etc.
Just surprised that an "apt-get upgrade" didn't bring down newer kernels, but hope those are pointers for anyone who wants to do kernel updates.