3 Configuring virtual machines Note that the VirtualBox EFI support is experimental and will be enhanced as EFI matures and becomes more widespread. While Mac OS X and Linux guests are known to work fine, Windows guests are currently unable to boot with the VirtualBox EFI implementation. 3.12.1 Video modes in EFI EFI provides two distinct video interfaces: GOP (Graphics Output Protocol) and UGA (Universal Graphics Adapter). Mac OS X uses GOP, while Linux tends to use UGA. VirtualBox provides a configuration option to control the framebuffer size for both interfaces. To control GOP, use the following VBoxManage command: VBoxManage setextradata "VM name" VBoxInternal2/EfiGopMode N Where N can be one of 0,1,2,3,4 referring to the 640x480, 800x600, 1024x768, 1280x1024, 1440x900 screen resolution respectively. To change the UGA resolution: VBoxManage setextradata "VM name" VBoxInternal2/UgaHorizontalResolution 1440 VBoxManage setextradata "VM name" VBoxInternal2/UgaVerticalResolution 900 The video mode for both GOP and UGA can only be changed when the VM is powered off and remains persistent until changed. 52