Microsoft confirms UEFI fears, locks down ARM devices
At the beginning of December, we warned the Copyright Office that operating system vendors would use UEFI secure boot anticompetitively, by colluding with hardware partners to exclude alternative operating systems. As Glyn Moody points out, Microsoft has wasted no time in revising its Windows Hardware Certification Requirements to effectively ban most alternative operating systems on ARM-based devices that ship with Windows 8.
The Certification Requirements define (on page 116) a "custom" secure boot mode, in which a physically present user can add signatures for alternative operating systems to the system's signature database, allowing the system to boot those operating systems. But for ARM devices, Custom Mode is prohibited: "On an ARM system, it is forbidden to enable Custom Mode. Only Standard Mode may be enable." [sic] Nor will users have the choice to simply disable secure boot, as they will on non-ARM systems: "Disabling Secure [Boot] MUST NOT be possible on ARM systems." [sic] Between these two requirements, any ARM device that ships with Windows 8 will never run another operating system, unless it is signed with a preloaded key or a security exploit is found that enables users to circumvent secure boot.