I can't seem to get the settings right to have both SGB borders and GBC enhanced games colors. I'm currently playing Dragon Warrior Monsters (black cart), and I can either get the SGB borders with B/W, or the colored version with no borders. If it's left on auto for both hardware and color, I get the border with no color, and setting color to "Original GBASP" doesn't change anything. Setting the hardware to GBC puts the game in color, but even if I set the borders to "on" it doesn't change anything. 

I can't claim to know the answer because I don't have a retron 5. But just for conversations sake, I wonder if the retron is just bringing a gameboy color and a super gameboy emulator to the table. And maybe your just toggling between one emulator and the other.

Does an emulator exist that brings super gameboy functionality and gameboy color colors?