ComcastNeil, can you please summarize what desired functionality you're shooting for re: audio on the X1 boxes? It's hard to understand what your objectives are for the box with all the reported issues and such from end users. The threads wander all over the place and it is hard to tell what to expect and when. It would be nice if you could state what you want the behavior to be eventually be once the issues have been worked out.
For example... Scenario 1:
HDMI from X1 to TV and SPDIF from X1 to RCVR: What is the expected audio behavior on the SPDIF? Can it bitstream regardless of the EDID info on the HDMI? Is there supposed to be a user setting to select which output from the X1 will have audio? Or does it send audio to both outputs unconditionally?
Scenario 2 (all HDMI, no SPDIF):
HDMI from X1 to RCVR, HDMI from RCVR to TV. CEC enabled, RCVR HDMI passthrough ON. What is the expected audio behavior?
Scenario 3:
Same as 2 but HDMI passthrough off.
There are no doubt other scenarios, but if you could build a sort of specification for your desired goals, then you could get some feedback and build consensus on what the engineers should be designing.