This is a noob question but I just wanted to know what an AP check is.
AP=Anti piracy -- When a game tries to determine if it's running on a flashcart instead of the retail game cartridge and behaves differently (most of the time it just crashes).
Just a guess: Are you referring to the official site of Sky3DS+, where they say "AP checks solved"?
Most modern flashcarts for DS (
not 3DS) games do not trigger AP-"features" and all games run like expected. When running DS games with nds-bootstrap/
TWiLight Menu++ you will have to patch newer ROMs in order to use the games.
For 3DS games: When you install free custom firmware and install the games (.CIA files) there are no such problems. It just works (and can do much more than expensive flashcarts like Sky3DS+).
Next time better put a "3ds noob question" to the
3DS NOOB PARADISE.