aperture_remove_conflicting_pci_devices() will disable firmware framebuffers before the native gpu driver takes over and could record the fact as hint, so userspace can figure later which device was used to display the boot screen. There also is the ConOut EFI variable, with the console output devices. That isn't always present though. When booting something based on edk2 it is there, when booting for example with u-boot in EFI mode it is not. take care, Gerd
