I currently have this problem. In order to work around it, I have so far configured grub to keep booting from the 5.11.0 kernel.
Next time there is a kernel upgrade, I expect Ubuntu will install the new kernel and delete my 5.11.0 kernel. I would like to prevent this, as the the 5.11.0 kernel is my last known working kernel.
I think I can prevent linux-image-5.11.0-46-generic
from upgrading by apt-mark hold
'ing it. But, as I understand it, this will just stick my kernel to the 5.11.0 version.
Instead I would just like to keep linux-image-5.11.0-46-generic
from being deleted when a new kernel version arrives, because I would like to test if newer kernel versions solve my problem, while I still have linux-image-5.11.0-46-generic
to fall back on.
Is this possible somehow?