Further to my post Ubuntu Testing Week - Ubuntu MATE 20.10
A fix has been implemented that corrects the issue I talked about there, alas it's consequence is Lubuntu/Xubuntu/Ubuntu (and possibly other flavors) no longer boot on
- hp dc7700
- hp dc7900
I plan to do some work on a workaround tomorrow (I've not read the last 5 comments on report & won't be able tonight). This is just an FYI (& please don't shoot the messenger!)