[Need Help] Unlocking Embedded Controller register access (Read/Write)

On the ASUS ROG GL504, reading the EC memory/registers yields nothing. Similarly, attempting to write to them fails.
I assume that this is some sort of protection. Any help would be appreciated; eg. is there a setup variable I can flip?
The bios is APTIO V. The setup image doesn’t seem to have any EC memory protection related variables.