Seems iffy (UeFI) to me

The latest in a catalog of efforts by Microsoft to keep  other players out of the operating systems field takes another leap for with the software giants attempt to tie the use of hardware to an operating system (which they certify). The Unified Extensible Firmware Interface  (UEFI) is a specification that defines a software interface between an operating system and platform firmware.

With the imminent release of Windows 8 the push is on to use this newish functionality to lock the choices for users down. It remains to be seen what the other O/S providers will do about this but it seems that even if the feature can be enabled to allow other o/s to boot – it will be required for Windows 8 to function.