"BIOS PSP Support disabled" is the only statement we have, in the form of a new option in the BIOS Setup.

That sounds like the equivalent of "HECI Disabled" for Intel BIOSes, which has been around for years.

It doesn't do anything to shut down the hidden CPU (PSP). It just sends a command to disable the bridge over to the main CPU. All the other ways of talking to the PSP remain open.