That is likely their own invention covered by their own patents (board technology) and copyrights (the BIOS). They have a right to license their patents, or not. We've seen what a disaster it was to the company to license, so their business decision was to stop.
It's quite different from the Lexmark case. A similarity would be if Apple designed their system to only write DVDs bought from them because of a part of their system that recognized only blank Apple DVDs. This decision says that such an action can be legally circumvented.
I think one of the funniest examples of abuse was the Agfa incident. True Type fonts have a bit in them that programs honor in whether to embed that font in a file or not. A font designer found that his designing application was always setting the bit to "don't embed" which he didn't want, so he wrote a program that quickly sets the bits on fonts to allow embedding.
Then he got a cease and desist order from Agfa (which sells fonts, mostly with the bit set to "do not embed") for distributing his program. The considered the bit to be copyright protection, and the program to be a circumvention device. Several letters later, with this smart guy knowing the law, they seem to have stopped harrassing him. But they had seemed to stop once before. All they need to do is take this case to court to ruin the guy financially.