* By sending an HECI command that says "hey ME, turn off your runtime" https://review.coreboot.org/c/coreboot/+/52800 . This is Somewhat Reliable; the method is well understood and seems to work but I'm not sure someone has done a deep dive audit into whether it could be re-enabled somehow.
* By patching the ME firmware itself - see the me_cleaner project, and methods documented here: https://puri.sm/posts/deep-dive-into-intel-me-disablement/ . This is Pretty Reliable; the runtime code has been deleted from flash.
* By setting a bit in the flash configuration, assumed to be added for the US High Assurance program: https://github.com/corna/me_cleaner/wiki/HAP-AltMeDisable-bi... , https://www.ptsecurity.com/ww-en/analytics/disabling-intel-m... . This is Mostly Reliable; the mechanism has been fairly aggressively reverse engineered and was added for a program with strict requirements.
* By sending an HECI command that says "hey ME, turn off your runtime" https://review.coreboot.org/c/coreboot/+/52800 . This is Somewhat Reliable; the method is well understood and seems to work but I'm not sure someone has done a deep dive audit into whether it could be re-enabled somehow.