I fully agree with Jonathan on this http://lwn.net/Articles/531082/:
In 2012, the shape of a solution for the UEFI secure boot problem came into view. In 2013, the full messiness of the secure boot situation will come to the fore. There are already reports of some secure-boot-enabled systems refusing to work right with the Linux "shim" solution; others will certainly come out. We are, after all, at the mercy of BIOS developers who only really care that Windows boots properly. We are also at the mercy of Microsoft, which could decide to take a more hostile stance at anytime; there have already been snags in getting the Linux Foundation's bootloader signed.
UEFI secure boot bears watching, and we owe thanks to the developers who have been laboring to make Linux work in that environment. But the problem of locked-down systems is much larger — and much older — than UEFI secure boot, and many of the systems in question already run Linux. Maintaining access to "our" hardware will continue to be a problem this year, just like it has been in the past. "Runs Linux" will continue to mean something different than "the owner can run their own software on it," and UEFI secure boot does not really change the situation all that much, especially for non-x86 systems.
Best Regards, Matthias