Good news Latest Firmware has been released for Rikomagic MK802 IIIS, fixes below points,
1. Fixed MAC address changeable issue;
2. Added WIFI hotspot function;
3. Improvied USB connected with PC method:
power on the stick–>setting->select “usb connect with PC”->power off,pull out the stick.
Then connect the stick with computer,stick will default USB Slave method.
4. Flash first partition from 504MB changed ot 1.23GB.
Firmware upgrade guide, please check here