Android TV Box - Tanix TX3 Mini

After looking for some RP3 replacement that can run Kodi I've stumble on GearBest offer for Tanix TX3 Mini for £19,99

Specs:
OS: Android 7.1
CPU: S905W up to 2.0 GHz, Quad core ARM Cortex-A53
GPU: Mali-450 penta-core, up to 750MHz+(DVFS)
RAM: 1GB/2GB DDR3
Storage: 16GB eMMC
Wifi: IEEE 802.11 b/g/n
Interface: DC Power Port,Ethernet,HDMI,SPDIF,TF card,USB2.0

Few things would be nice to have is:

5G WiFi
Bluetooth

Box support 4K but with firmware I got (Amlogic/p281/p281:7.1.2/NHG47L/20170906:userdebug/test-keys) that simple didn't work.
So I went to http://www.tanix-box.com and searched for firmware upgrade (as update from System settings didn't work)

On Tanix website there was update for 4K fix
Link:
https://mega.nz/#!OclU1YDC!sLBCTp69Ec1NYX7PqJmhzj8UmpVt77CN6VuHKrDlVuM
Link to guide:
http://www.tanix-box.com/124/how-to-flash-tanix-tx5/

Inside is new img file: TX3Mini-20171107_Tanix-Box_com.img that you will need to transfer to device and update with Update&Backup tool

After downloading and upgrading firmware I got 4K working normally :)