Is it possible to download the original version 20.04 release somewhere? Somewhat frustratingly, though there are separate download directories for 20.04 and 20.04.1, 20.04/ contains 20.04.1 files.
The reason I want this is because I was running 20.04 quite happily on a Ryzen 2400G system, but when 20.04.1 was released, I upgraded. However, on reboot I'm getting a kernel panic. Before I report this formally, I want to drop back to 20.04 in an attempt to verify that upgrading to 20.04.1 is somehow the cause.
It seems the original Ubuntu 20.04 LTS iso file is hidden or removed. My guess is that those responsible don't want people to use it because of the serious boothole bug (and maybe also because of other bugs, that are fixed in the first point release 20.04.1 LTS).
I checked today, and could find original buntu 20.04 LTS iso files from April of flavours, for example
A new version is released to apply fixes to the bugs found in previous version. Although it is also true that new version could contain more bugs than previous one.
Therefore I recommend trying to fix your 20.04.1 issue rather than rolling back. However it's totally up to you.
Here is the download link for your Ubuntu 20.04 : http://old-releases.ubuntu.com/releases/20.04/
You can probably bring up the GRUB menu by holding down the Shift key when powering on the machine, select "Advanced options for Ubuntu" and then select a specific kernel to boot into.