Ubuntu 20.04 domu problem

[Bill MacAllister <bill@xxxxxxxxxxxxx>]

I am working on moving our Xen servers to Ubuntu 20.04 and am having 
problems creating domu's using xen-tools.  The xen-create-image 
execution completes but the resulting domu does not boot.  Here is the 
command line I am using for the build.
  /usr/bin/xen-create-image --hostname=zoot.ca-zephyr.org \
      --memory=4Gb --genpass=1 --size=40Gb --dhcp --vcpus=2 \
      --pygrub --swap=2Gb --role=udev,/etc/xen-tools/role.d/cz-bionic \
      --dist=bionic --arch=amd64

The resulting container does not have grub installed.  When I look at ? 
I see that the attempt is to install grub.  But the "grub" package is 
not available on 20.04.
At this point I started just hacking.  I changed to using pvgrub by 
commenting out the 'bootloader' parameter in the domu configuration file 
and added the line 'which resulted in booting the container to the 
"grub>" prompt.  But with the domu's /boot empty this of course did not 
lead anywhere.  I then just hacked on 
/usr/share/xen-tools/focal.d/82-install-grub-legacy and changed the 
install line to 'grub2'.  With that the domu boot directory was not 
empty, but the boot still stopped at the 'grub>' prompt.
So, now that I have done this the wrong way I would be very grateful is 
someone could point me in the correct direction.
Thanks in advance,

Bill

--
Bill MacAllister <bill@xxxxxxxxxxxxx>