I tested sound fx with spotify. Working great.
Gesendet von meinem Mi 4i mit Tapatalk
tested with google play music, spotify and tunein and all worked great.
You flash it via TWRP recovery and make sure it's Mi4i Toolkit v4 here - https://docs.google.com/uc?id=0B0pkb-PnDIp8cTc4NENOODFRazA&export=download
You need to download the Mi PC Suite to go back to MIUI via fastboot mode. You can download it her...