I think you may need to have someone look at your setup. If neither H9 will learn the DMC buttons, that suggests that either you have a cabling/connection issue, or that there is a problem with the setup or hardware of the DMC.
The facts that the DMC may be faulty and has been in storage for 6 months may be connected. If you could test it with other equipment or borrow another one, you might learn something. I could believe one faulty H9 but probably not two.
