Mantic & LTS dual booting bug

[Liam Proven]

I upgrade 2 laptops from 23.04 (and a VM from the beta) to 23.10
yesterday. All went very smoothly.

Hasn't fixed the odd bug I've seen though:

I have 2 machines where I made a backup copy of the root filesystem
before upgrading to 20.04.

(Both started out as the same copy of 13.10, a decade ago -- I duplicated it.)

When the 20.04-22.04 upgrade was successful, I duplicated the root
partition again (I changed the UUID and /etc/fstab files, obviously.).

So both boxes are BIOS booting, with MBR partitioning, and have:

[Primary part: Windows] {Extended part: [Ubuntu primary] [Ubuntu
spare] [shared /home] [swap] }

Since I had a good copy to fall back on, I upgraded the spares to
22.10. Worked very well. So I upgraded them to 23.04. Now I have a
problem.

Both machines have 2 SSDs. One has the GRUB from 22.04, one has the
GRUB from 23.04.

So depending on which SSD I choose to boot from, I get different GRUB menus.

The 22.04 GRUB boots 22.04 fine, but in 23.04, the GUI never appears.
I get stuck at a blank screen. Linux is running and I can sometimes
switch to a virtual console and press Ctrl-Alt-Del to reboot.

The 23.04 GRUB boots 23.04 fine, but 22.04 fails on a black screen the same way.

It's not critical but it's annoying.

Yesterday I upgraded one of these to 23.10. No change. Upgraded OS
works perfectly, though.

-- 
Liam Proven ~ Profile: https://about.me/liamproven
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