Stock rom for the Reko mk819 and similar can be found here:
http://pan.baidu.com/s/1zOOYV
Model: rk30sdk
Android: 4.2.2
Kernel: 3.0.36+
(JDQ39 build)
Vendor Software Version: RK3066_R-BOX_ANDROID4.2.2-SDK_V1.0.0_130308
I think this unit has a combo BT/Wifi chip (Ampak ap6210), this rom works with that chip.