Sometimes you need to bump up the size of your SD card to get a game like Super Smash Bros Demo to work. I got a download code from Club Nintendo but it kept freezing on a black screen when I tried to run it!
People eventually figured out you need an SD card 4gb or larger in order to run it. I was only using the 2gb one given with the 3DS so what the hell, time to find a spare SD card laying around the house.
Just copying the files directly from one SD card to another won't work. Fortunately, some smart cookie developed "emuNAND Tool" that does all the hard work for you.
- Have a working emuNAND as the source SD card.
- Create an extra emuNAND on the target SD card (see "Creating your EmuNAND" section of a previous tutorial)
- While your 3DS is creating an emuNAND, grab "emuNAND Tool v1.0.1".
- Open "emuNAND Tool" and click "Extract emuNAND" to extract the emuNAND from the source SD card to a file (it doesn't take that long, probably a minute or two at most)
- By the time your target SD card is done creating a new emuNAND, take it out of your 3DS and put it into your computer.
- Click "Inject NAND to emuNAND" and select the file you saved from the source SD card earlier.
- It will now copy the emuNAND files across to the target SD card.
- Once it's done, you've now got a replica of your previous emuNAND.
- Put it back into the 3DS and use it as you normally would.
Note: Games downloaded from the eShop won't be copied. You'll have to re-download those.