Thanks for confirming JRiver and JRemote work. It’s not part of my regular testing unless someone reports an issue.
JRiver has a unique feature over the Lumin app and Roon for those who need it: the ability to play SACD ISO file, and stream it as a DSD track via UPnP. This reminds me I need to find out whether SACD ISO file can be played using Audirvana to Lumin hardware.
That’s a real shame, it could easily go from U1 mini to U2 mini.
Hey, really sorry that you’re having to put up with issues with your U2. No one wants to have to deal with weirdness that didn’t previously exist in their chain.
That said though, what you’re describing is nearly ALWAYS DC in the AC line. If you plug your U2 in someone else’s system or take it back to your dealer and have them plug it in into some of their systems. It should be really easy to troubleshoot.
I’m not a good candidate because I power my U2 with an external PS, and it makes a huge improvement to the audio quality. But the primary reason I’m responding here is for folks not to have a bad impression on what in my experience is a world class streamer that can sound as good as the U2X for a fraction of the cost with a simple (warantee voiding 
mod.)