Success!!! and wow, I just feel stupid right now. It was actually all good the first time I tried to do this, and it was good earlier today on my second attempt.
The issue was I have a Global Village modem card in there and after installing the memory card (since it now has chips on the side facing the modem card), it was shorting against the modem card... Argh!
These chips are the same thickness as the stock ones on the other side, I guess there isn't much room. I put a piece of mylar between the modem card and the memory card, and it works now.