To get your Rockchip player into "upgrade mode" all you do is this,
1) Switch the player OFF using the main on/off switch.
2) Hold down the "MENU" or the "PLAY" button and keep it held down.(try the other buttons if these dont work)
3) Connect the usb to the player.
4) Wait for about 10 seconds before releasing the menu key.
5) You are now in "RockUSB" upgrade mode!
6) Then just Start ConsumerUpdate and upload a working firmware and try it!
additional information can be found on Rockchip player recovery is here':-
http://www.mympxplayer.org/rockchip-...de-vt6686.html
You may like to try the firmware I used to recover my player with it's the same screen size as yours :-
http://www.mympxplayer.org/rockchip-...276-df612.html
I hope you can get your player back.