This only affects UEFI VMs running Ubuntu. A default Ubuntu installation includes the linux-modules-extra-<kernel-version>-generic package, which provides the bochs driver—required for proper VGA display in the Xen Orchestra console. If this package is removed, the console display becomes scrambled.

Run the following command to install the missing package (replace <kernel-version> with the version in use by the OS):

sudo apt install -y linux-modules-extra-<kernel-version>-generic

source: https://docs.xcp-ng.org/vms/#distorted-display-console-on-ubuntu-uefi-vms