Download latest Android Lollipop 5.1.1 stock firmware for ProBox2 Ex+ TV Box from here, here or here. Download SD card firmware version from here, here or here. To flash this firmware from PC use this video tutorial. To flash firmware on this box from SD card read this article.
Archive: PROBOX2-EX-PLUS_20151125 / PROBOX2-EX-PLUS_20151125-sdcard
Model: ProBox2 Ex+ TV Box
Image file size: 593 MB / 603 MB
Platform: Amlogic S812
Update file name: PROBOX2-EX-PLUS_20151125.img / PROBOX2-EX-PLUS_20151125.zip
Build number: Android/n200/n200:5.1.1/LMY47V/20151125:user/test-keys
1. Fixed Google Play app “Google Play Services has stopped” Error Message when insert some USB input devices (keyboard / Mouse).
2. Fixed Add-ons of Kodi would be removed after OTA Firmware upgrade.
3. Fixed Settings app “Unfortunately, Settings has stopped.” Error Message occur randomly.
4. Fixed write permission on USB storage device like torrent file could not start on TF card / USB drive.
Caution: Please do not update firmware unless you know what you are doing, you really want it or it is absolutely necessary. Firmware updates may occasionally have bad results, like bricking your device, temporarily or permanently. The firmware update process is done entirely at your own risk. Before attempting to update the firmware, back up your data.