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Cemu is a Wii U Emulator.

Website: https://cemu.info/

GitHub: https://github.com/cemu-project/Cemu

Compatibility List: https://compat.cemu.info/

This page is for the Proton build of Cemu. EmuDeck includes the native build of Cemu as an optional install. If you choose to download the native version, both versions will remain installed. One quick way to tell the difference is to compare the two GUIs. For the Native version of Cemu, visit Cemu Native.

Native Cemu:

Proton Cemu:

Cemu Proton Table of Contents

  1. Getting started with Cemu
  2. Cemu Tips and Tricks

Getting started with Cemu

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IMPORTANT: Cemu is shifting away from encrypted ROMs (WUX, WUD). It is strongly recommended you use decrypted ROMs (Loadiine, WUA). Decrypted ROMs do not need any additional configuration and should launch without any issue.

Cemu is a fairly straight-forward emulator to set up, if you use decrypted ROMs. Place your ROMs in Emulation/roms/wiiu/roms. Do not install your games. No additional setup is required.

Read the Configuration section to learn more about Cemu and its folder locations.

For updates and DLC, read How to Manage DLC and Updates.

To launch your ROMs in game mode, use Steam ROM Manager and use one of the following parsers to play your Wii U ROMs:

  • EmulationStation-DE
  • Nintendo WiiU - Cemu (.rpx) - Proton or Nintendo WiiU - Cemu (.wud, .wux, .wua) - Proton
    • Read the File Formats section to learn more about these various file formats
    • .rpx and .wua are decrypted ROM formats
  • Emulators

If you intend on using encrypted ROMs, proceed to the Setting up Cemu Questionnaire.

Setting up Cemu Questionnaire

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IMPORTANT: Cemu is shifting away from encrypted ROMs (WUX, WUD). It is strongly recommended you use decrypted ROMs (Loadiine, WUA). Decrypted ROMs do not need any additional configuration and should launch without any issue. If you use decrypted ROMs, you do not need the following questionnaire.

Setting up Cemu Questionnaire

  1. Is your ROM encrypted? If yes, do you have a keys.txt in the right place with the correct keys for your games in the keys.txt file?
    1. What are keys?: Keys are required to decrypt Wii U ROMs. Your keys.txt needs to contain keys (one key per game) that must be dumped from a Wii U console. Any other method of obtaining keys is piracy and cannot be discussed here or on the EmuDeck discord.
    2. Which Cemu ROM Formats are encrypted?: File Formats
    3. keys.txt Location: Emulation/roms/wiiu
    4. If your ROM is NUS Format (a folder with .h3 and .app files), you will need to decrypt your ROM into the Loadiine format (folder format with three subfolders - code, content, meta). Decryption methods cannot be discussed here or on the EmuDeck discord.
  2. Is your ROM decrypted?
    1. Which Cemu ROM Formats are decrypted?: File Formats
    2. If your ROM is decrypted, place the ROM in Emulation/roms/wiiu/roms. Your game should launch without needing any keys.
  3. If you are getting an Unable to launch game error, did you place the keys.txt in the right place?
    1. keys.txt Location: Emulation/roms/wiiu
  4. If you placed the keys.txt in the right place, and your ROM is still not working, does your keys.txt have the correct key for the ROM?
    1. Even if you placed a key for your game in keys.txt, you may still have the incorrect key.
  5. Did you transfer your ROM from another computer and did you compare file sizes to ensure it transferred successfully?
  6. Did you turn on Proton in Steam? If yes, turn it off. If you are unsure, check.
    1. How do I check?: The Dangers of Proton

Cemu Proton Configuration

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IMPORTANT: Cemu is shifting away from encrypted ROMs (WUX, WUD). It is strongly recommended you use decrypted ROMs (Loadiine, WUA). Decrypted ROMs do not need any additional configuration and should launch without any issue.

  • Type of Emulator: Windows Executable Through Proton
  • Executable Location (Cemu Script): Emulation/tools/launchers/cemu.sh
    • Use cemu.sh to launch Cemu in desktop mode.
  • Executable Location (Windows EXE): Emulation/roms/wiiu/cemu.exe
    • Do not launch Cemu in desktop mode with cemu.exe.
  • Emulator Folders Location: Emulation/roms/wiiu
    • Contains the following folders:
    • controllerProfiles
    • gameProfiles
    • graphicPacks
    • memorySearcher
    • mlc01
    • resources
    • roms
    • shaderCache
  • Cemu Configuration File: Emulation/roms/wiiu/settings.xml
  • Persistent Storage: Emulation/roms/wiiu/mlc01/
  • ROM Location: Emulation/roms/wiiu/roms
    • Note the second roms folder in the path.
    • Do not put DLC / update files in the ROM path. Refer to How to Manage DLC and Updates for DLC and updates.
    • Place your game ROMs here, do not install your game ROMs
  • keys.txt Location: Emulation/roms/wiiu
    • The keys.txt is only necessary if the Wii U ROM is encrypted.
    • keys.txt needs to contain keys (one key per game) that must be dumped from a Wii U console. Any other method of obtaining keys is piracy and cannot be discussed here or on the EmuDeck discord.
  • Saves Location:
    • Symlink: Emulation/saves/Cemu/saves/
    • Target: Emulation/roms/wiiu/mlc01/usr/save

Works With

  • Steam ROM Manager
  • EmulationStation-DE

Cemu Proton Folder Locations

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These file locations apply regardless of where you chose to install EmuDeck (to your internal SSD, to your SD Card, or elsewhere). Some emulator configuration files will be located on the internal SSD as listed below.

$HOME refers to your home folder. If you are on a Steam Deck, this folder will be named /home/deck (you will likely not see deck in the file path when navigating using the file manager).

Paths beginning with Emulation/.. correspond to your EmuDeck install location. If you installed on an SD Card, your path may be /run/media/mmcblk0p1/Emulation/roms/... If you installed on your internal SSD, your path may be /home/deck/Emulation/roms/..

Emulation/roms/wiiu/

wiiu
├── Cemu.exe
├── controllerProfiles
│   ├── controller0.xml
│   ├── controller0.xml.bak
│   ├── deck2.xml
│   ├── deck2.xml.bak
│   ├── deck3.xml
│   ├── deck3.xml.bak
│   ├── deck4.xml
│   ├── deck4.xml.bak
│   ├── Deck-Gamepad-Gyro.xml
│   ├── Deck-Gamepad-Gyro.xml.bak
│   ├── Deck.xml
│   └── Deck.xml.bak
├── gameProfiles
│   ├── default
│   └── example.ini
├── graphicPacks
│   └── downloadedGraphicPacks
├── keys.txt
├── log.txt
├── memorySearcher
├── mlc01
│   ├── readme.txt
│   ├── readme.txt.bak
│   ├── sys
│   └── usr
├── resources
│   ├── ca
│   ├── de
│   ├── es
│   ├── fr
│   ├── hu
│   ├── it
│   ├── ja
│   ├── ko
│   ├── libusb-1.0.dll
│   ├── nb
│   ├── nl
│   ├── pl
│   ├── pt
│   ├── ru
│   ├── sharedFonts
│   ├── sv
│   ├── tr
│   ├── uk
│   ├── WinGamingInput.dll
│   └── zh
├── roms
├── settings.xml
├── shaderCache
│   ├── driver
│   ├── info.txt
│   ├── precompiled
│   └── transferable
└── title_list_cache.xml

Emulation/roms/wiiu/mlc01

wiiu/mlc01/
├── sys
│   ├── sys
│   ├── title
│   └── usr
└── usr
    ├── boss
    ├── save
    └── title

The Dangers of Proton

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IMPORTANT:

There is outdated info on the internet that indicates you need to set Proton on Cemu or on games added for this console by Steam ROM Manager in Steam. Turning on Proton is not necessary. DO NOT set Proton Compatibity on Cemu or Cemu games added to Steam. Do NOT set STEAM_COMPAT_MOUNTS in parameters.

Turning on Proton is not necessary because EmuDeck created a custom script to launch Cemu Proton. Turning on Proton through Steam breaks EmuDeck's custom script.

Do not open the Compatibility screen in Game Mode. Do not touch any of the settings on the Compatibility screen in Game Mode.

proton

How to Update Cemu

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How to Update Cemu

  • Through the Update your Emulators & Tools section on the Manage Emulators page in the EmuDeck application
  • Manual file replacement of Cemu.exe
  • Refer to How to Swap Out AppImages and Binaries for instructions

How to Switch Between Cemu Versions

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EmuDeck includes a feature that allows you to swap between Cemu 1.26 (stable), 1.27, and 2.x.

To swap between versions

  1. Open EmuDeck
  2. Click the Manage Emulators button
  3. Click Update your Emulators
  4. Click Update AppImages and Binaries
    • This includes the Windows version of Cemu
  5. Check Nintendo WiiU Emu (Proton)
  6. Select which Cemu version you would like to use
    • IMPORTANT: The GitHub link is the latest 2.x version of Cemu (version 2.0.36 in this image)
    • IMPORTANT: The GitHub link/2.x version of Cemu is still the Windows version of Cemu, the link does not refer to the native version

How to Launch Cemu in Desktop Mode

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How to Launch Cemu in Desktop Mode

  • Launch Cemu (Proton) from the Applications Launcher (Steam Deck icon in the bottom left of the taskbar)
  • Launch the script from Emulation/tools/launchers, cemu.sh
  • Launch the emulator from Steam after adding it via the Emulators parser in Steam ROM Manager

Cemu Proton File Formats

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  • Loadiine (rpx)
    • Three folders (code, content, meta)
    • Folders should be inside a folder with the name of the game. This game folder is placed in Emulation/roms/wiiu/roms (note the second roms)
    • Visual Reference:
    • Decrypted, does not require keys.txt
  • WUA (requires Cemu 1.27.1 or higher)
    • Decrypted, does not require keys.txt
  • WUX
    • Encrypted, requires keys.txt in Emulation/roms/wiiu/
  • WUD
    • Encrypted, requires keys.txt in Emulation/roms/wiiu/
  • NUS
    • A folder with .h3 and .app files
    • Encrypted, can be decrypted into a Loadiine (rpx) folder. Decryption methods cannot be discussed here or on the EmuDeck discord.

IMPORTANT:

  • Some of these formats may require keys. We cannot help you get these. Place your keys.txt in: Emulation/roms/wiiu
    • keys.txt needs to contain keys (one key per game) that must be dumped from a Wii U console. Any other method is piracy and cannot be discussed here or on the EmuDeck discord
  • Once you put ROMs in place, you must refresh the list of games by right clicking in the Cemu UI and clicking Refresh Games List
    • Your game will not show up in Cemu until you refresh
  • Refer to How to Manage DLC and Updates, for DLC and Updates.

How to Convert to WUA

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The WUA format is a compressed version of the Loadiine format. It contains your base game, DLC, and updates all in one single file. The WUA format is a lot less fuss than the other formats, requires no keys, and is the most friendly format for EmulationStation-DE.

Here's how to convert to WUA:

Note:

  • Encrypted ROMs (WUX, WUD, NUS) cannot be converted to WUA
  • Cemu only supports WUA on 1.27 and above
    • You cannot convert ROMs to WUA on 1.26, the stable build of Cemu

Tutorial

  1. Open Cemu
  2. Click Tools, Title Manager
    1. Visual Reference:
  3. Either search for your ROM or find it in the list
  4. Select the ROM with the word base in the Type column
  5. Verify the pop-up prompt has your base game, your update, and your DLC files
    1. You can either place these update and DLC files in Emulation/roms/wiiu/roms temporarily or install them: How to Manage DLC and Updates
  6. Wait, it may take a while
  7. Right click in Cemu, and click Refresh Game List to refresh your file path in Cemu to the newly created WUA file

How to Manage DLC and Updates

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Preface

DLC and Updates must be installed using the title manager. DLC and Updates are saved to mlc01, in the Emulation/roms/wiiu folder.

IMPORTANT: Do not keep your DLC and update files in Emulation/roms/wiiu/roms. After installing these, you may either delete or move the files to a backup location. Keeping DLC and update files in this directory will create duplicates in Steam ROM Manager.

Installing DLC/Updates Through Cemu

  1. Launch Cemu on Desktop Mode
  2. Click File in the top left, click Install game title, update, or DLC...
    1. Visual Reference:
  3. Click / and either navigate to your SD card, /run/media/mmcblk0p1 or to your home folder /home/deck
  4. Select the parent folder (named <Game Name: Update ###> or <Game Name: DLC Y>) of your update or DLC
  5. On the right, you will see code, content, and meta
  6. Select meta, and click Open in the bottom right
    1. Visual Reference:
  7. Wait a moment, and your DLC or update will be successfully installed. Repeat for each DLC or update

GIF:

Manual DLC / Update Install Method

You can manually position the update and DLC files in the correct spot without using the Title Manager in Cemu.

The base of this operation is your mlc01 folder.

The folder structure for the mlc01 is as follows: mlc01/usr/title/

Inside the title folder you need a 0005000e folder for updates and a 0005000c for DLC

inside those folders, you put a folder with the id of your game.

TitleID Database

US Breath of the wild for example:

  • Update: mlc01/usr/title/0005000e/101c9400/ {code, content, meta } go here

  • DLC: mlc01/usr/title/0005000c/101c9400/ {code, content, meta } go here

Cemu Proton Hotkeys

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Cemu comes with a Steam Input profile for Hotkeys. When playing Cemu ROM shortcuts through Steam, the EmuDeck - Controller Hotkeys profile will automatically be applied so you may use the below hotkeys. For more info, see Emulator Button Combinations Profile.

When using a frontend (ES-DE, Pegasus, or the emulator itself), the EmuDeck - Frontend Controller Hotkeys will automatically be applied. Hold Start for a few seconds to switch to the action set required to use the below hotkeys. For more info, see Emulator Frontends Button Combinations Profile.

Hotkey Cemu
Toggle Full Screen Select + R3
Toggle Screens L4 or R4 or Start + DPad Left or Select + Y
Swap Screens L5 or R5 or Start + DPad Down or Select + X
Stop Emulation Select + Start or hold L5 or hold R5
Blow Mic R3

Note

Known Issues

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  • Xenoblade Chronicles X crashes on 1.27.1 with high frequency.
  • Cemu will fail to launch on versions 1.27.1 through 2.0-16 when there's no internet and Gyro is enabled.
  • Cemu versions 2.0-17 and above will work offline with Gyro enabled.
  • The Legend of Zelda: Twilight Princess HD's missing UI graphics are fixed in 2.0.4, but this version brings some performance regressions in other games.

Cemu Tips and Tricks

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How to Configure Gyro

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Gyro for Cemu requires SteamDeckGyroDSU. SteamDeckGyroDSU can be installed via EmuDeck, or it can be installed manually.

Gyro only works with the Wii U Gamepad (enabled by default). If you changed your controller layout to the Pro Controller, gyro will not work.

Read How to Use the Wii U Pro Controller Configuration to learn how to apply the Pro Controller layout on a per game basis.

Visit SteamDeckGyroDSU to learn how to install and utilize SteamDeckGyroDSU.

How to Optimize Performance (Power Tools)

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Visit Power Tools to learn how to optimize performance using Power Tools.

How to Configure Multiplayer

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  1. Open Cemu
  2. It's recommended you enable multiplayer on a per-game basis. Turning on additional controllers can disable single player controls in a handful of games
  3. Right click a game, click Edit Game Profile
  4. Click Controller
  5. To the right of each Controller (Controller 2 through Controller 4), select the respective Deck # profile (Deck 2 for player 2 and so on)
  6. (Optional) You may need to re-arrange the controller order in Game Mode for your controllers to function as expected. See How to Re-Arrange the Controller Order for more information

How to Use the Wii U Pro Controller Configuration

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In some some games, the initial screen will prompt for a controller configuration: Wii U Gamepad or Wii U Pro Controller.

For example:

If you prefer to use the Wii U Pro Controller layout, you need to change the controller profile in Cemu. Make sure to change controller profiles on a per-game basis so it is persistent on EmuDeck updates.

Tutorial

  1. Right click the game, click Edit game profile
  2. Click the Controller tab
  3. Change the profile to Deck
  4. When you launch a game, one of the following two things will happen:
    • Some games will prompt you to choose a controller layout, select the Wii U Pro Controller
    • Some games will automatically switch to the Wii U Pro Controller configuration

How to Optimize Breath of the Wild

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IMPORTANT: You need Version 208 of Breath of the Wild to use FPS++. Read How to Manage DLC and Updates to learn how to install game updates for Cemu.

How to Configure Cemu

  1. In Desktop Mode, open Cemu (Proton)
  2. Right click Breath of the Wild, click Edit graphic packs
  3. Click Download latest community graphic packs
  4. Click the + to the left of Mods
  5. Check the box to the left of FPS++
  6. Change the mode to Advanced Settings
  7. Change the Framerate Limit to 40FPS
  8. Close out of Cemu

How to Configure Game Mode

  1. In Game Mode, open Breath of the Wild
  2. Click the ... (the QAM) button
  3. Click the battery icon
  4. Click Advanced View
  5. Enable Use per-game profile
  6. Set the refresh rate to 40
  7. Read How to Optimize Performance to learn how to use the battery menu and Power Tools to further increase performance for Breath of the Wild

After doing the steps in the above two sections, Breath of the Wild will run at a stable 40 FPS with temporary occasional hiccups in new areas while it compiles shaders.