Pro Tip: Use NUSspli directly on the Wii U. This homebrew app downloads WUP files directly from Nintendo’s servers (using a valid title key) and installs them without a PC.
If you do not own a Wii U console, the open-source emulator Cemu is the gold standard for playing Wii U games on Windows, Linux, or Steam Deck.
However, Cemu does not use raw WUP files directly. It requires a decrypted or keyed format.
How to convert WUP to Cemu-ready format: wii u wup roms
Note on Keys: To decrypt WUP files on Cemu, you need the Wii U common key (a 32-byte hexadecimal key). This is not distributed with the emulator. You must legally obtain this via your own console keys (using apps like dumpling on a modded Wii U).
First, let's clarify the terminology. "ROM" (Read-Only Memory) is a general term for a digital copy of a game cartridge or disc. In the Wii U's case, the native game format is not a single file like an .iso or .rom but a structured folder of data. A "WUP ROM" refers to a game dump created in the WUP (Wii U Package) format, often with the file extension .wud (Wii U Disc) or, more commonly for installable backups, a folder containing .app, .h3, .cert, .tmd, and .tik files.
This structure mirrors how the Wii U's internal storage and USB drives hold game data. Therefore, WUP files are not meant to be opened or run directly like an emulator ROM. Instead, they are installation packages designed to be installed onto a Wii U console's internal memory or a formatted USB drive. Pro Tip: Use NUSspli directly on the Wii U
If you are coming from the world of NES, SNES, or even Wii emulation, you are likely used to file extensions like .iso, .gba, or .nes. The Wii U, however, operates differently.
WUP stands for Wii U Package.
When you download a game from the Nintendo eShop, it isn't a single file like an ISO. It is a structured folder containing encrypted content, tickets, and metadata. When people talk about "WUP Roms," they are referring to these digital backups that mimic the structure of the official eShop downloads. If you do not own a Wii U
Inside a standard WUP folder, you will typically see files like:
This differs from the Loadiine format (which uses .rpx files and /content/ folders). While Loadiine was the gold standard for homebrew years ago, WUP installations are now the superior method. They allow you to install games directly to the Wii U system menu (or USB drive), meaning you can launch them just like a retail disc or an official eShop purchase.
If you are installing The Legend of Zelda: Breath of the Wild via WUP, you might notice the game takes a long time to load when traveling between areas or shrines. This is because the WUP format installs the game to the system's storage architecture in a specific way.
For this specific title, some enthusiasts prefer the older Loadiine format because it loads assets slightly differently, sometimes resulting in smoother performance on USB drives. However, for 95% of the library, the WUP installation method is superior because it allows for proper sleep mode functionality and integration with the Wii U main menu.