Thanks Obama.
According to a post at Tiny Cartridge, a recent firmware update on the 3DS–which automatically starts downloading, mind–has effectively blocked most flashcarts on the market.
The changelog, they note, doesn't really mention any of this–which makes sense, I guess, why would it? The news comes from SuperCard, manufacturers of carts. Tiny Cartridge notes that the issue with this update is that flashcart manufacturers will need to create new products in response, meaning people will have to buy new carts. Not such a great situation for people who have spent money on these carts.
Is it likely that people would go through the trouble? Considering the high price of games otherwise, I'm guessing so! Not that everyone that uses flashcarts uses them for piracy, of course. This marks a highly aggressive campaign on Nintendo's part to keep piracy off the 3DS–unlike the DS. The DS had what seemed to be hilariously easy piracy. The 3DS, not so much–to the detriment of the homebrew scene, though.