I just updated my Ubuntu 14.04 and got a new kernel. This new kernel is not working properly for me so I booted the previous version. Let's call this good old working version "3.13.0-24.47".
Now, I want to keep this "3.13.0-24.47" version until I decide to delete it manually. I want to be able to upgrade my kernel each time there is a new version in hope of getting the one which works again. Until then, I want to use the "3.13.0-24.47".
I'm afraid that next update will delete my "3.13.0-24.47" version because there are only two kernel versions available at a given time on my system (/boot).