USing a flashcart on an emulator is rather pointless. It's like using an Everdrive on a Retrode to play on a PC emulator. Why? Just boot the ROM directly from the PC. With the RetroN5 being Android based you can bet there will be a hack that allows for loading of ROMs from the SD card. Android is known inside and out in terms of how it functions. Making the hack will be nothing for a decent developer or Android hacker. Getting it flashed should be easy too since it has the SD card slot.