Ubuntu – Why are the official/stable 4.* kernels marked unstable

For your release of Ubuntu,

1. Ensure you have the -update and -security repositories enabled.

2. sudo apt update (or sudo apt-get update)

3. Install the linux-image-generic metapackage to install the latest kernel that is packaged and tested for your release of Ubuntu. The metapackage will pull in several dependencies including the actual kernel packages themselves.

   Using the metapackage will ensure you get upgrades as they become available.

Note that apt cannot remove kernels from other sources - you must clean up those yourself.

I ended reverting to the default kernel from ubuntu and it all workend as expected.