While marketed for "4K," the RK3128 is a budget-tier chip primarily suited for 1080P streaming and light web browsing. It often struggles with modern, heavy applications like the latest official YouTube app, which may require using a web browser for smoother playback.
3.5mm jack for legacy composite analog television connections. 1 x SPDIF Port: Digital audio output. The Firmware Conundrum: Real vs. Fake OS Versions
Look at RKBatchTool. One of the connected device squares should turn (Loader Mode) or Blue (MaskROM Mode). Once it changes color, release the reset button. 3. Flash the Firmware