That's why I always emphasize that TPM (UEFI/SecureBoot/Boot Guard etc.) are not the right way for open source systems (Linux etc.).
The Linux community should stop to fiddle with locked-down boot systems. They actually should boycott locked-down systems and only support hardware vendors who officially support Linux. Many of them are presented at LinuxGizmos. I believe that such hardware vendors are much more open to the demands of the Opensource Community than vendors who produce locked-down systems.
These are four different technologies. Some of them help your freedom. Some of them hurt it. Some of them have nothing to do with your freedom at all. It doesn't really do anyone any favors to lump them all in the same category; it certainly doesn't make hardware vendors inclined to think you're making cogent arguments.
UEFI has nothing to do with secure boot (apart from the fact they're compatible).
I run Linux on my Thinkpad, with UEFI-only enabled, secure boot disabled, and UEFI will boot my kernel directly using EFISTUB - no more screwing around with bootloaders. It's awesome!
There's even ways to use SecureBoot with various distros [1]. Sure it's a pain, but it can be done. Having and using teh tech is a different issue from vendors hindering what you can do with your hardware.
The Linux community should stop to fiddle with locked-down boot systems. They actually should boycott locked-down systems and only support hardware vendors who officially support Linux. Many of them are presented at LinuxGizmos. I believe that such hardware vendors are much more open to the demands of the Opensource Community than vendors who produce locked-down systems.
http://linuxgizmos.com