OK everybody, made some interesting discoveries tonight, I tested this out after reading this comment on a YouTube video about the Legends Flashback, it turns out that in order to unlock the SD card slot you need to have a folder named GAME on the root of the SD card, you do not need any firmware. Out of the box I found that NES (.nes), Genesis (.bin), SNES (.fig), and Atari 2600 (.a26) roms work with just the stock unit. However, after doing this a couple of the built in games stopped working for me (Maui Mallard and The Jungle Book), so you may want to hold off putting Genesis roms on this system. I tested this with a Sam's Club deluxe version, but I don't think it would be much different with the standard edition.