Updating Ubuntu only to discover that the kernel update has brought you to a black screen – never fun.
Read it in this blog
Once you manage to get back into your Ubuntu PC, you will be feeling a lot better. You have your important data backed up and of course, you can now take steps to put this other kernel out to pasture. First, open up a terminal window and type the following to figure out which kernel you are running now which is working for you.