Yes, they do https://libreboot.org/faq.html#amd https://libreboot.org/faq.html#amd. They even said recently that they are not planing to letting you disable it/

Yes, they do https://libreboot.org/faq.html#amd https://libreboot.org/faq.html#amd. They even said recently that they are not planing to letting you disable it/remove it/share the source of it https://news.ycombinator.com/item?id=14803373 https://news.ycombinator.com/item?id=14803373. Ironically enough, using an Intel processor with ME cleaner is more free than using an AMD processor.