Steps to install Google play store on MiBOX3_Pro

Device: 

manufacturer: Xiaomi

model: MiBOX3_PRO (MDZ-18-AA)

MIUI TV版本: 1.4.6（稳定版)

Prerequisites (Tools & Packages )

1) 360超级ROOT from http://root.360.cn/

  PermRoot.apk
  (Note: Use the 7.1.6 version that come with a green icon; newer version with cyan color icon doesn't work; Request older version from 360.cn forum or alternatively from www.apkhere.com/down/com.qihoo.permmgr_7.1.6_free. Use at your own risk )

2) apk files from Gapps packages

  67ae3a402c705c8ec97d6d05364e8697  gapps-5.1-arm64-2015-07-17-15-08.zip

     Unzip and extract the following apk files:

1. PrebuiltGmsCore.apk (from /arch/priv-app/PrebuiltGmsCore/)
2. GoogleServicesFramework.apk (from /common/priv-app/GoogleServicesFramework/)
3. GoogleLoginService.apk (from /common/priv-app/GoogleLoginService/)
4. Phonesky.apk (from /common/priv-app/Phonesky/)

     !! Rename the PrebuiltGmsCore.apk to GmsCore.apk !! 

3) Terminal emulator

  Example: jackpal.androidterm-1.0.70-71-minAPI4.apk

4) Google play store apk (from apkmirror etc)

5) Get ready a wireless/bluetooth keyboard

Steps

0) You may want to follow the link to enable 3rd party apk installation and change the UI language: How-to change UI language

1) Root the device

     Install PermRoot.apk. Launch 360超级ROOT & click the <跳skip> on upper right corner to enter the main screen. Click the center BIG icon in middle to start.

2)  Install terminal emulator and grant the root access

    Install jackpal.androidterm-1.0.70-71-minAPI4.apk. Launch the emulator and switch to root user

  >  su -     (Click Accept / 允许 when 360超级ROOT prompt)

  #  cd /

3) Remount /system rw

  # mount -o rw,remount /system

4) Copy the Gapps apk files to respective locations

   # cd /system/priv-app

   # mkdir GmsCore GoogleServicesFramework GoogleLoginService Phonesky

   # chmod 755 GmsCore GoogleServicesFramework GoogleLoginService Phonesky

   # 

   # df   (check your path to USB thumbdrive)

   (Note: Modify the following path to your Gapps apks in thumbdrive)

   # cp /storage/usbotg/usbotg-sda1/<path to gapps>/GmsCore.apk GmsCore/

   # cp /storage/usbotg/usbotg-sda1/<path to gapps>/GoogleServicesFramework.apk GoogleServicesFramework/

   # cp /storage/usbotg/usbotg-sda1/<path to gapps>/GoogleLoginService.apk GoogleLoginService/

   # cp /storage/usbotg/usbotg-sda1/<path to gapps>/Phonesky.apk Phonesky/

   # chmod 644 GmsCore/GmsCore.apk Google*/* Phonesky/Phonesky.apk

   # sync

   # reboot

5) Install the Google Play Store and YouTube from thumbdrive etc

----- That's all

DISCLAIMER. The instructions listed here can cause permanent damage to your device if applied incorrectly. Use at your own risk!

Information and hints from kane @ http://www.cnx-software.com/2016/04/12/xiaomi-mi-box-3-enhanced-pro-mediatek-mt8693-benchmarks-and-system-info/#comment-525919