Welcome. The more members can get involved the better, especially anyone who is a c/c++ programmer.
We don't have any source code or info on the Rk28xx series players atm only Rk26xx and Rk27xx.
I have successfully compiled and ran the firmware for rk27xx and rk26xx.
The firmware ran ok on my rk27xx from tinydeal, I could play music ok, but there was an issue with screen drivers so I got no display just a backlight.
My unbranded Rk2706 from Tinydeal is quite good to play with, I was able to go into recovery mode using the reset hole without opening up and it's cheap from tinydeal.
There are basically 3 types on this page:-
http://www.tinydeal.com/index.php?ma...1v3mc8v4kvb3q3(the touch screen is the worst of the 3)
www.mp4nation.net have a good selection of branded chinese players too, most but not all are rk27xx