boot error, cannot upgrade kernel

[Ralf Mardorf]

On Thu, 6 Jan 2022 22:13:40 -0700, Gary Aitken wrote:
>As complained about above, there is no /etc/default/rcS
>
>Can anyone tell me what's going on

Hi,

I can't tell you what's going on, but I can comment on /etc/default/rcS.
This file is aimed to contain defaults for initscripts, but Ubuntu and
almost all other Linux distros, migrated to systemd, hence initscripts
are replaced by systemd units. Ubuntu and almost all other Linux distros
don't follow the UNIX alike approach to do one things well and to use
human readable scripts for startup, it's using a binary blob that does
startup not well and tons of other things, completely unrelated to the
boot process. However, another bloatware asking for trouble is GRUB,
even while it has got some pros. You are likely encountering one of the
GRUB issues, that never get a fix. I stay away from GRUB, migrated to
syslinux a long, long time ago. To fix your issue consider to stay away
from GRUB repair features, try repairing your non-booting install using
a live media, e.g. an Ubuntu USB stick. GRUB is a bootloader, it's not
aimed to repair broken installs.

https://en.wikipedia.org/wiki/Unix_philosophy

Regards,
Ralf