As proposed by Der Spiegel at http://www.spiegel.de/international/world/catalog-reveals-nsa-has-back-doors... the NSA seems to be interested in subverting BIOSes, lower-level disk roms and the like.
May I request you loudly announce how one checksums one's coreboot, and in principle other BIOSes, so that one can see if anyone has changed firmware critical to one's security.
--dave