What does HackerNews think of heads?
A minimal Linux that runs as a coreboot or LinuxBoot ROM payload to provide a secure, flexible boot environment for laptops and servers.
Definitely worth reading the Wiki: https://osresearch.net/
Can be run on a variety of laptops, including a ThinkPad X230. Ships by default on Librem laptops. Uses the second-to-last approach described by the article (TOTP-based).
I wanted to mention the excellent HEADS project (as in the other side of TAILS): https://github.com/osresearch/heads
This talk is great: https://trmm.net/Heads_33c3
I remember when UEFI became a thing and people were complaining in linux forums that the keys are controlled by the manufacturers and 'the whole thing is a ploy by microsoft to kill linux' (UEFI is just a convoluted standard way to write BIOS in a certain way).
Now we can control the keys, all we need to do is kick UEFI to the curb and use linux from BIOS all the way to the DE/WM (coreboot..).
Turns out we can turn the boot process into a chain of kexec's and simplify everything greatly.