After this step:
5. Launch the app (from your app drawer). Grant root to let it install drivers. I've always gone with super audio quality; I suppose it's up to you. It may ask you if it can modify some files to disable power saving...just let it happen. Reboot again.
I checked driver status -> Enabled: No
I don't know reason, I used this app on my previous phones normally...
LG Optimus 2x / ROM: Jelly Cream 1.4 /Baseband version: V30A / Kernel: Kowalski M1 / KoB 0.7
Samsung Galaxy S5 G900F / Stock ROM G900FXX1ANE2/ Towelroot