First, I should confirm whether they're looking for a ROM of Lemur for the 3DS. But I also need to be mindful of legal issues. ROMs are copyrighted, so distributing them is against the law unless the game is abandonware, which isn't clear. The user might not know the legal side, so I need to explain that while helping them if they have a legitimate copy.
Also, check if the user is asking about developing a custom ROM (like a "develop piece"), which would be different. But since the query is about "lemuraoid 3DS ROMs," likely not development, just accessing the game.
I should outline the possibilities: legal access through online stores if possible, the process of extracting a ROM (with the legal caveats), and alternative methods like emulators with a backup of their own game. Also, maybe mention that some games are available on the eShop or other platforms now if they're interested in playing legally.