Thank you for inputs.
I am told by McIntosh engineer that accidentally keeping WIFI/Net and STANDBY/ON buttons pressed will wipe out the firmware on Phorus chip inside. And my suspicion is that this is what may have happened. This is a software design oversight and should have been easily avoidable. A system with barely four buttons must never allow something like this to happen, however accidental. Hoping no other issue...
Now, to fix the unit back into operation, firmware must be reloaded. Any experiences with how much is the ballpark charge for a simple reloading of firmware, shipping costs aside?
Kota1, I did use it as a streamer only connected to my preamp DAC over coaxial digital cable. It works pretty well. I also once directly connected it to my Bryston amp, but God save you if you fiddle with volume control on PlayFi mobile device, esp. if your amp is Bryston 4BSST 300WPC. I wouldn't recommend it. Preamp vol control is for safety.