Download Android 4.4.2. KitKat stock firmware for Rikomagic MK902S TV Box from here or here. Download previous firmware from here. More details about Rikomagic MK902S TV Box here. Download Rockchip Driver Assistant v4.4 from here and download Rockchip Batch Tool v1.8 from here.
Archive name: MK902S_170621
Image file name: MK902S_170621.img
Firmware size: 352 MB
Model: Rikomagic MK902S TV Box
Platform: Rockchip RK3188 / RK31
Firmware: Android KitKat 4.4.2 stock
Model number: MK902
FW version: 4.4.02
Boot number: 2.31
SDK version: RK30_ANDROID$(PLATFORM_VERSION)-SDK-v1.00.00 \
Build number: RKM MK902-eng 4.4.2 KOT49H eng.pl.20170620.140448 test-keys
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.