I got it working, but I had to fiddle a bit, I found some hints in the Xserver log, if I remember correctly it was at
/var/log/Xorg.0.log
There was a config file /root/xorg.conf.new, I copied it to /usr/share/X11/xorg.conf.d/98-custom.conf.
cp /root/xorg.conf.new /usr/share/X11/xorg.conf.d/98-custom.conf
Probably you can also symlink it, it shouldn’t make a difference?!
I think the crucial part is the "Device" section, where you specify to use fbdev driver.
Btw I had to use some “hacky” scripts to get Hyper-V working on a Win 10 Home machine 