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nosklo edited this page Feb 27, 2018 · 15 revisions


This is a tool to automatically update cemu related files. This first version only updates the graphic packs, more is planned.


  • Updates your graphic packs to latest version, so you always have fresh graphic packs.
  • Works fine with zero configuration, just drop it on your cemu folder and run
  • Automatically detects your games and only decompresses the packs for those games
  • Can filter the resolution packs to only keep some resolutions you choose
  • Can load a special folder (by default named "vault") where you keep your graphic packs that are not in the repository, or that you have edited and want to keep untouched between updates
  • accepts the same parameters as cemu.exe and launches cemu for you
  • You can associate windows Open with... dialog for .rpx, .wud and .wux files to upd_cemu.exe so that double-clicking on a game will auto-launch it on cemu. Also allows creating shortcuts directly to game files and they just work
  • downloads use asynchronous networking and has a graphical cancellable progress bar
  • very configurable with easy to generate json config file, can be easily integrated in other tools


Here's a video by BSoD Gaming that shows installation and usage of the tool.


This is beta software. It is working for me and for many users but please make backup of everything, because I cannot guarantee it will work for you. If you find any issues please send them to the issues page.


The tool is written in python language, it should work in python v3.5 or above and aiohttp. If you have that, just put the .py files in cemu folder and run

If you're on windows and don't want to install python and required programming libraries, you can download a windows .exe from here.


The tool is fully automated, all you have to do is run it. Since it calls cemu.exe in the end, you can use upd_cemu instead of cemu.exe every time and guarantee your packs are always up-to-date every launch.

Here's the sequence of operations when you run the tool:

  • The first time the tool runs, a backup of your existing graphic packs will be created in the folder graphicPacks_old.
  • A download will start to get the latest graphic packs community zip from the repository.
    • If a file already exists with the correct name, it will be used instead and no download will occur.
    • During the download, a progress bar will appear and if you close it the download will be cancelled.
  • The existing graphicPacks folder will be completely deleted, and the tool will unpack all packs that can be used with the games you have played from the new zip.
  • After unpacking, the downloaded zip file will be automatically deleted.
  • The tool will then call cemu.exe for you.
  • Next time you run the tool, it will do nothing if nothing changed, and call cemu.exe directly. If something changed it will do a new unpack of the zip.
  • If something goes wrong, the tool will generate a upd_cemu_crashlog.txt file, please make sure you're using the latest version of the tool, then send the log to me here.

Further Configuration

add/remove games

  • If you want to add a game, just play that game once and run the tool again.
  • If you want to remove a game, delete that game's save file from mlc01/usr/save folder.

filter resolutions

You can filter resolution files by creating a file named res.txt and writing the resolutions you want one per line like this:

720p ultrawide

Next time the tool runs, it will grab only the packs for those resolutions. All non-resolution packs will still be unpacked.

The "vault"

The vault is a place to store extra graphic packs that are not in the official community repository. It can also be used when you want to edit a pack to customize it.

By using the vault, those packs will be copied to the graphicPacks folder every time you run the tool, so they won't be erased when there is a new release of the packs.

Just create a folder named vault in your cemu folder and put the packs you want to keep. You can change the location and name of the folder by editing the configuration file.

File association

You can associate the wii u game files (.rpx, .wud and .wux files) directly to upd_cemu. If you do that, when you double click on a game it will run. You can also create shortcuts to the game files and they will just work.

These images show how to configure windows to do that:

Config file

The config file is a json file named upd_cemu.json with a json object. These are the recognized keys:

  • cemu_path: Path to find cemu.exe and the graphicPacks folder. Default: same path as the tool.
  • download_dir: Path where the .zip file will be saved when downloaded. Default: same path as the tool.
  • delete_downloads: If the .zip file will be deleted after unpack. Default: true.
  • resolution_file: Name of the file containing the resolutions to unpack. Default: res.txt
  • resolutions: Resolutions detected in the file above last run. If they differ it triggers a new unpack.
  • last_graphic_packs: Last downloaded graphic packs filename. If the filename in the repository is different it will trigger a new download.
  • last_cemuhook: Reserved for the future feature to update cemuhook
  • keep_dir: Name of the folder containing graphic packs to be copied after the update. Default: vault
  • gameid_list: List of last detected games. If this changes it triggers a new unpack.
  • update_gameid_list: If you set this to false, it will stop detecting your games every time, and will only unpack the games listed in the gameid_list setting above. Default: false.
  • exec_cemu: Set this to false to prevent cemu.exe to be executed at the end. Default: true
  • extra_params: You can define extra parameters to be passed to cemu.exe here. Example: ["-nolegacy"]. Default: empty []
  • fullscreen: Automatically add the fullscreen flag -f when running a game. Default: true

Command-line parameters:

  • -c or --config: use this to specify another location for the config file. By default it reads upd_cemu.json in the same folder it is in.

Any other command line arguments are forwarded directly to Cemu.exe, so you can use any arguments you would use with cemu.exe here.


  • Does it need admin rights?
    • No. It should run without any specific rights. Just make sure you can write to the folders specified in the config file.
  • I'm using linux, how do I define which wine I want to use to run Cemu.exe?
    • You need to put it first in the PATH. You can also set WINEPREFIX before running the tool.
  • 720p better color depth pack for Breath of the Wild is being unpacked, but I didn't choose this resolution!
    • That is not a question. The Better Color Depth pack is not considered a resolution pack, but a color pack. There is no 720p pack for Breath Of The Wild because that is already the default game resolution.
  • My resolution format is not being detected, how do I make it work?
    • Use the width x height format (example: 1920x1080), that will always be detected.
  • Your .exe has a virus!
    • That is also not a question. The .exe is automatically generated. If you don't want to use it you can download the source and run it directly, or generate a .exe yourself.
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