I recently purchased a second standard 3DS (used.) I put a 4GB SD card in it, and received an error:
"Write protection is enabled on the SD card. The software on the SD card cannot be displayed."
Figuring it was just that card, as the write protect switch wasn't in the "Lock" position, I tried an 8GB card that I had laying around. Same error. Both cards work perfectly in my other system, and I've reformatted them in FAT32 format with no luck in the second system.
I ran a system update, and my current version is "Ver. 7.1.0-16U"
Any thoughts?