Download Android Nougat 7.1 stock firmware for Acemax KIII Pro TV Box from here or here. Download previous firmware from here. Download Android 6.0 stock firmware for Acemax KIII Pro TV Box from here.
Model: Acemax / Mecool KIII Pro TV Box
Image file size: 866 MB
Platform: Amlogic S912
Build number: Amlogic/q20x/q20x:7.1.1/NHG47L/20170816.104603.V0619:userdebug
Other: Supporting DVB-S2
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.