For focal and bionic I started lxd vms with 4-8GB each (the allocate over 4GB parts I don't think are actually needed, lol), rebuilt initrd with the initrams tools hook, upgraded grub to the ubuntu14.1 and made sure it booted.
Then I downgraded grubs again to ubuntu14 and made sure it failed with out of memory again.
For focal and bionic I started lxd vms with 4-8GB each (the allocate over 4GB parts I don't think are actually needed, lol), rebuilt initrd with the initrams tools hook, upgraded grub to the ubuntu14.1 and made sure it booted.
Then I downgraded grubs again to ubuntu14 and made sure it failed with out of memory again.