VNC port displays for UEFI_CSM firmware which does not support GOP
It is a known issue within the FreeBSD community that UEFI_CSM does not work with graphics output protocol. When we create a VM the VNC port is still displayed. When the user attempts to connect with VNC they will see a blank screen.
Using UEFI_CSM the user could attach with a serial console. We could display info about which /dev/nmdm device could be used to attach with serial. We could write an open console feature similar to what we have for jails which does this automatically as well. Although I am not sure how hard that would be. If we wanted to go that route we could consider bhyveload, or grub-bhyve as well as options. The grub-bhyve option would be substantially harder to configure. The bhyveload option would just work out of box more or less as long as FreeBSD is used. Or we could drop the UEFI_CSM firmware altogether from the menu, and stick with EFI only until a serial console feature could be further developed which is what I would lean towards.