I think you need to be fast enough to connect with vnc to see the "press any key to boot from the cd rom", otherwise you get the uefi shell. I think you can also start the installation from the uefi shell. FS0 should refer to the cd rom with the install iso: so just type in the uefi shell: fs0: then: cd \EFI\BOOT finally: BOOTX64.EFI