I don't think that my player don't have enough buttons to play in console games.
For example, most of Sega Genesis games don't require 6-Btn gamepad,
only 3-Btn gamepad, and my player has all the necessary buttons (7)
Here's my player: Soundbreeze Mp-401 - MyMPx
(UP,DOWN,LEFT,RIGHT, AB stands for A, M stands for B, >|| stands for C;
however, the player don't have the separate button for START/PAUSE,
but it's possible to implement the "holding" algorithm :
if hold C button for more than 3 seconds, then START/PAUSE)
But there's one BIG problem: not all of the Rockchip players have the same number of buttons;
maybe your player has only 5 (or 6) buttons.