If you own physical discs and are legally backing them up, these are the titles you should prioritize:

A ROM is a digital copy of the data from a read-only memory chip—in this case, from a Wii U game disc or a digital download from the Nintendo eShop. A standard Wii U game disc holds up to 25 GB of data (similar to a single-layer Blu-ray), while larger titles like Xenoblade Chronicles X or Super Smash Bros. for Wii U can push closer to 15-17 GB after compression.

Unlike older cartridge-based ROMs (like NES or SNES), Wii U ROMs are often distributed in specific formats designed for emulators like Cemu (the leading Wii U emulator). These formats include:

The Wii U is a time bomb. The console uses a proprietary NAND flash memory that is prone to failure (especially Hynix chips). Millions of consoles will simply stop booting within the next decade. Without ROM dumps, the digital-only games—especially indie titles like The Fall or Swords & Soldiers II—will vanish forever.

Organizations like The Video Game History Foundation and No-Intro are working to catalogue and preserve Wii U ROMs in secure, non-public archives. They argue that copyright law should allow libraries to provide remote access to out-of-print games, similar to microfilm or MP3s.

Until the law catches up, individual dumping is the only ethical and legal path.