1. HTC M8
2. Android 6.0 Marshmallow stock rom (Sense 7.0) 6.12.401.4 + firmware ElementalX 7.0.0
3. http://forum.xda-developers.com/htc-one-m8/general/m8-audiophile-thread-t2833054 plus http://forum.xda-developers.com/showthread.php?t=2705613 "enable high definition audio"
Tested with Poweramp alpha-build-703: no Hi-Res audio