OK, I did a little research into SSDT_EC.aml. It won't help this condition (from what I read anyway).
EC, "Embedded Controller," has to do with USB ports, etc. It (from what I can tell), adds an "EC0" section in the ACPI area. I already have such a section, and my USB ports function correctly. Per the "test", I can plug in an iPhone and it reports its presence just fine, in fact my ports all list their occupying devices correctly.
Back to square one...