Hi Guys, oh my quite a flurry of activity this afternoon while I was away! Thanks so much for all your input, and I will answer the burning question of the moment. My root / partition is formatted with Ext4, what I think was once called Reiserfs or something like that. I know little about all these different formats, just that I tried Btrfs once, got into some trouble with it, and skedaddled back to Ext4 and stuck with it ever since because it has  never cause me any trouble that I know of.

But like I said, my knowledge of the advantages versus the disadvantages of different formats isn't worth the paper this note is written on! FWIW the last thing I expected to be talking about, when I started this thread/query is the format of my partition! LOL Amazing where things can lead to...

    Marc...

On 2024-01-21 23:21, Felix Miata wrote:

Darryl Gregorash composed on 2024-01-21 22:56 (UTC-0600):

Andrei Borzenkov wrote:

You confuse "boot previous kernel" with "boot from snapshot".

I think that, if I boot from a snapshot that had a different (previous)
kernel version, then I am booting a previous kernel, yes? ;)

I suggested to boot a previous kernel, not an entire previous operating system,
which is what booting a snapshot amounts to; to change fewest practical potential
failure points at a time, not many. Booting a snapshot facilitates getting back in
business quickly well, but not so much isolating or solving a problem arising from
updating.

But what is there in anything Marc has posted so far that suggests simply recreating the initramfs file will solve the problem? If the kernel update somehow did not complete properly, then I doubt dracut/mkinitrd will resolve the issue.
Assuming that Marc cannot simply do a system rollback, would it make sense to
a) boot into the previous kernel
b) do an unconditional update on the following packages:
kernel-default
kernel-default-extra
kernel-default-optional
c) reboot
?