Funny Story.... embarrasingly so....I turned it on when I got home, waited...and amazing it worked perfect. It turns out I just was not patient enough. I have a few stv carts, so I was used to swapping them out and games loading right up. I didn't take into consideration the flash cart load time, and even though I did wait a little before, I'm thinking I always gave up, probably just afew seconds before the game actually loaded when I was trying originally. And for the cartridge error -- seems like user error. I didn't even remove the multicart and it worked the first time once I plugged it in. I had the jumpers set to Soukyugurentai when I got home though, and then switched to ribbon cable for the LCD selector. Everything worked flawless. Thanks for letting me know about the SDXC cards not working though - one of the cards I bought was XC, whereas the other 2 were HC. Somehow I never saw this printed anywhere, in all of my searches. In the end though, I guess it was just my impatience that got the best of me. Darksoft, you are awesome for getting back to me so quickly, especially because this thread is like 6 years old and you are still very attentive to it. You guys Rock!! Thanks for everything!!