A ROM (Read-Only Memory) is a digital file that contains an exact copy of the data from a game cartridge or disc. In the context of the Wii U, a “Wii U ROM” is a digital dump of a game originally released on a Wii U optical disc. These files typically come in formats such as .wud (Wii U Disc), .wux (compressed WUD), .loadiine (extracted game files), or .rpx (the main executable file).
Loadiine / Decrypted Folder: A folder containing code, content, and meta subfolders. This is the standard decrypted format that Cemu has supported for years.
Encrypted Files (.wux / .wud): These often need to be "unpacked" using tools like CDecrypt before they can be played on an emulator. 2. Using ROMs on a Physical Wii U
First, let’s clarify terminology. Strictly speaking, a ROM (Read-Only Memory) is a file extracted from a cartridge-based system (like the NES or GameBoy). The Wii U uses optical discs (25GB proprietary discs). Therefore, the correct technical term for a ripped Wii U game is an ISO or a loadiine folder structure.
If a ROM requires the GamePad screen (e.g., Nintendo Land, Star Fox Zero), set Cemu to "Separate GamePad view" or use a mobile app like Cemu Companion.
Homebrew Development: Developers creating unofficial software or games for the Wii U often test their work using ROMs of homebrew applications or legally dumped retail games.