How to Add Games to Citra MMJ – Dumping, Formats & Game Library Setup

Getting games into Citra MMJ is the first real hurdle for new users — and it’s the step where most mistakes happen. This beginner-friendly guide walks you through the entire process: legally dumping your own cartridges, understanding which file formats work, and setting up your game folder so your library shows up correctly.

No jargon assumed. Follow it top to bottom.

The Legal Way: Dump Your Own Cartridges

Let’s be clear from the start: you should only play games you own. The legitimate way to get 3DS games into Citra MMJ is to dump the cartridges you physically own using a modded Nintendo 3DS. Downloading ROMs from the internet is piracy, and this site doesn’t provide or link to game downloads — ever.

The good news: dumping your own games is straightforward once your 3DS is set up, and you only need to do it once per game.

What you need

Item	Why
A Nintendo 3DS / 2DS / New 3DS (any model)	The hardware that reads your cartridges
Custom firmware (CFW) installed on the 3DS	Required to run homebrew dumping tools
GodMode9	The homebrew tool that dumps cartridges to files
An SD card with free space	Dumps are 500MB–4GB per game
The physical game cartridges you own	The source of your dumps

Dumping a cartridge with GodMode9 (step by step)

1. Insert the game cartridge into your modded 3DS.
2. Launch GodMode9 from your homebrew launcher (hold Start while booting on most CFW setups).
3. Navigate to the cartridge: go to [C:] GAMECART in the drive list.
4. You’ll see the game’s .3ds file. Select it and choose Copy (or note the option to dump directly).
5. Navigate to [0:] SDCARD and paste — or use GodMode9’s built-in dump option to write the file to your SD card.
6. Decrypt if needed. GodMode9 can dump in decrypted form — choose the decrypted output option. Citra MMJ requires decrypted dumps; encrypted files will show a black screen or fail to boot (see our black screen fix guide if you hit this).

⚠️ Before Proceeding: Make sure your dump is decrypted. This is the single most common reason a freshly added game refuses to boot. GodMode9’s dump menu has an explicit decrypted-output option — use it. If a game shows only a black screen after adding it, an encrypted dump is the first thing to check.

What about digital games you bought?

If you own digital games on the 3DS eShop, GodMode9 can dump those too — they produce .cia files (installable archives). These work in Citra MMJ as well; see the format table below.

Understanding 3DS File Formats

You’ll encounter several extensions. Here’s what each one is and whether Citra MMJ accepts it:

Format	What it is	Works in Citra MMJ?
.3ds	Raw cartridge dump	✅ Yes — the standard format, recommended
.cci	”CTR Cart Image” — same as .3ds, different extension	✅ Yes — identical to .3ds
.cxi	Executable image (the game’s code without the full cart wrapper)	✅ Yes
.cia	”CTR Installable Archive” — eShop/installable format	✅ Yes — install via the emulator’s CIA installer
.3dsx	Homebrew executable format	⚠️ For homebrew apps, not commercial games
.elf / .axf	Developer/debug formats	❌ Not for normal use

Practical advice:

• For cartridge dumps, .3ds is the simplest choice — dump it, copy it, load it.
• For digital purchases, use .cia and install it through Citra MMJ (there’s an “Install CIA” option in the menu). Installed titles then appear in your game list like cartridges.
• Ignore the other formats unless you’re doing homebrew development.

How big should the file be?

A legitimate 3DS game dump is typically 500MB to 4GB. If your “game file” is 12MB, it’s incomplete or fake — it won’t boot. This is a quick sanity check before you start troubleshooting anything else.

Setting Up Your Game Folder in Citra MMJ

Once you have your decrypted dumps on your phone (or on your computer, to transfer over), it’s time to point the emulator at them.

Step 1: Create a games folder

On your phone’s storage, create a dedicated folder — something like:

Internal Storage/CitraGames/

Keep all your game files here, in one place. Don’t scatter them across Downloads and random folders; a single organized directory makes the game list reliable and backups easy.

Step 2: Copy your game files in

Transfer your dumped .3ds / .cci / .cxi files into that folder. You can use a USB cable from your computer, or copy directly from the 3DS’s SD card with a card reader or file manager app.

💡 Tip: Rename files clearly when you copy them — e.g. Pokemon Moon (USA).3ds instead of CTR-P-BNAA.3ds. GodMode9 dumps often have cryptic filenames, and clear names make your game list far more usable.

Step 3: Add the folder in Citra MMJ

1. Open Citra MMJ.
2. Tap the + button or Add Games (usually prominent on the main screen).
3. Navigate to the folder you created (CitraGames) and select it.
4. The emulator scans the folder and populates your game list with box art and titles.

Step 4: Refresh the game list

Added new games later? You don’t need to re-add the folder:

• Pull down on the game list to refresh, or use the Refresh option in the menu.
• New files in the folder appear automatically after a refresh.

Installing .cia files

For .cia dumps (digital games):

1. In Citra MMJ, open the menu and choose Install CIA (sometimes under File or Tools).
2. Select your .cia file.
3. Wait for the installation to finish — larger games take a minute or two.
4. The game now appears in your game list permanently. You can delete the .cia file afterward to save space (the installed copy lives in the emulator’s data directory).

Organizing a Growing Library

Once you have more than a handful of games, a little organization goes a long way:

• One folder for cartridges (.3ds/.cci), installed CIAs handled by the emulator itself.
• Subfolders by genre or series are fine — the emulator scans recursively, so CitraGames/RPG/ and CitraGames/Racing/ all show up in one list.
• Back up your saves separately. Your game files are replaceable (you own the cartridges); your save data isn’t. Our save data backup guide shows you how to protect it.

Troubleshooting: Game Won’t Show Up or Won’t Boot

Problem	Likely cause	Fix
Game doesn’t appear in the list	File in an unscanned folder, or wrong extension	Move it to your games folder and refresh
Black screen on boot	Encrypted dump	Re-dump as decrypted in GodMode9
”Invalid file” error	Corrupted or incomplete file	Check file size; re-dump or re-transfer
CIA won’t install	Corrupted CIA or low storage	Re-dump; free up space and retry
Game boots but crashes quickly	Missing system files or bad settings	See the black screen fix guide

What’s Next

With your library set up, you’re ready to actually play. Good next steps:

• Complete beginner guide — full emulator configuration from scratch
• Best settings — tune performance once games are running
• Best version — make sure you’re on a solid Citra MMJ build
• Controller mapping guide — set up a gamepad for real controls

One careful dump session per game, one organized folder, and your library is done — enjoy it.