20.04 hangs on shutdown or restart

The more I try to use 20.04 the more sure I become that it is indeed inferior to 16.04.

I installed Mate 20.04 on an "Atomic Pi" a small IOT class machine, with all upgrades. Got it running OpenVINO and Coral TPU AI code, thought maybe it has been updated enough to be OK now. Then I tried to restart it.

Hangs on reboot or shutdown. Either from the menus or with sudo shutdown -r now.

Turning off splash and quiet in the grub boot options shows its in a watchdog crash loop after reaching the shutdown or reboot target.

I've tried the various grub boot options suggested via Google for older variations and none work.

I know it not a hardware issue because if I boot an SD card with Ubuntu-Mate 16.04 no issues on shutdown or reboot.

Hardware is an Intel Atom Z8350.

I appear to have found a workaround, something is wrong with the mei module.

sudo rmmod mei_hdcp mei_txe mei

left me with a working system that rebooted without issue, but of course the mei modules were installed again.

So I edited /etc/modules/d/blacklist.conf and added:
blacklist mei
blacklist mei_txe
blacklist mei_hdcp

So now it appears I can reboot and shutdown cleanly.

its running kernel 5.4.0-58-generic and the Atom Z8350 is x86_64