Most PX3 units belong to the MTC series manufactured by FYT or similar factory systems. Older generation boards.
Fixes issues where steering wheel buttons stop working or vehicle climate data fails to display. rkpx3 mcu update
Example atomic sequence:
This forum hosts the largest collection of Android head unit firmware on the internet. Use a browser translator to navigate their RKPX3/MTC-type directory threads. Most PX3 units belong to the MTC series