How to enable LayeredFS on a Luma-ready 3DS

LayeredFS is an on-the-fly game patcher add-on for Luma that enables users to play mods and ROM hacks.

How does it work? Basically, each game contains a partition called RomFS that contains all of the assets that the game requires to work. Things like levels, models, the interface, they're all contained within the RomFS. What LayeredFS does is intercept the calls to the files and check if they're present on the SD card. If they are, it sends the game the modified file instead, resulting in a modded game. This method is particularly useful because you can mod a game easily, without needing to repack it and install it.

You must know if you've installed a CFW on your console. To do that, shut your console down, then hold SELECT and turn it on again. If you see the Luma configuration screen, congrats, your 3DS is Luma-ready. If not, you'll have to install it. Since installing the CFW is a long and tedious process that varies depending on the model and the firmware version, so I'm gonna link to the central guide:

3DS Hacks Guide

A complete guide to 3DS custom firmware, from stock to boot9strap.

3DS Hacks GuideNintendo Homebrew

Keep in mind that the minimum version of Luma to use LayeredFS on is version 7.0. If you have a lower version, be sure to update. To update, copy the boot.firm file to the root of the SD card from the latest release, found on:

Releases · LumaTeam/Luma3DS

Noob-proof (N)3DS “Custom Firmware”. Contribute to LumaTeam/Luma3DS development by creating an account on GitHub.

GitHubLumaTeam

If your Luma installation is installed in your internal NAND (eg., if you haven't set up an emulated NAND), you may also have to follow these steps:

Finalizing Setup

Full sighax CFW Guide

3DS Hacks GuideNintendo Homebrew

Anyways, once your console is modded with an updated enough version of Luma, enter the Luma configuration menu by holding SELECT at startup. Check that Enable game patching is enabled, and if not, enable it. Save with Start and reboot.

Now, LayeredFS is enabled, though we don't have any method to check if it works, besides downloading a mod and applying it. So what's what we're gonna do.

You can download any mod for any game you own and follow the instructions on the page. Regardless, the general process is the following:

1. Download the mod's .zip file
2. Check the contents. If the file contains an alphanumerically titled folder that starts with 00040000, you can copy that directly to sd:/luma/titles, otherwise you must create a sd:/luma/titles/TITLEID folder (where TITLEID is the Title ID of the game/region combo you're modding; you can find a list of Title IDs here) and copy the contents of the .zip to that folder.
3. Launch the game.
   • If the game looks unmodded, check that you haven't missed any of the steps above.
   • If your console crashes, you must check that the files haven't corrupted somehow.
   • If all goes well, congrats! You now have a system that can patch your games on-the-fly.

That's all there is to the process. Happy modding!