I'm talking about the flashcards firmware
The flashcard doesn't even work using those files...
The top screen becomes just white and the the bottom screen black. The sd card, slot2 and favorites icons are still on the bottom but all the text is gone and I can't go into the games...
I ran into that issue with my DSTwo a LOT! I fixed my problem with doing EXACTLY what @juggernaut911 said!
Also make sure that you format your FlashCards microSD card to FAT32 @32 kilobyte cluster size.
In short - If you use Windows:
Capacity:
<Size of your formatted SD Card>
File system
<FAT32 (Default)>
Allocation unit size
<32 kilobytes>
Thats all you have to worry about.