A couple things, you may need to reboot all your HDMI connected devices. Unplugging them from power. I would start with the TV, then the dvd player, Etc. This would be a simple HDMI reset. If that doesn't work, try resetting the 975.

Please feel free to give me a call, M-F 9:00am - 5:00pm EST, at (866) OUTLAWS.

Spoke to Jim at Outlaw, he straightened me out. I had been messing with the very last option under the 975's "Audio Input" menu ("HDMI Out to TV") and he said to leave it off, that it was not relevant to the ARC functionality. That seemed to work, now I can switch between the two inputs to the TV (Antenna and the HDMI ARC) while retaining audio. I am still experiencing what appear to be handshake issues, so will do a bit of troubleshooting there, but the connections and settings appear to be working. Thanks, everyone!

Thanks for the update! It's always nice to see the resolution on things like that.