Hmm, I was under the impression that of the BSDs, only FreeBSD supported UEFI. (As well as MacOSX, of course.) But it appears that despite Theo’s previous comments on UEFI 🙂 that there might be some UEFI support in OpenBSD eventually:
From last year, GSOC’14 for OpenBSD (UEFI and GPT), I’ve not studied to see if these have been upstreamed yet:
http://www.google-melange.com/gsoc/project/details/google/gsoc2014/mmu/5639274879778816
From 2 days ago, a new OpenBSD-centric boot loader:
https://github.com/yasuoka/openbsd-uefi
It looks like the latter project needs some hardware help, besides the author’s VIAO, if you can help them out…
Firmware Security 