For users seeking a functional ("fixed") ROM, the file extension is a key indicator of reliability.
: Icons and code suggesting two-player support was planned long before it was officially added in later console ports. Official Resource
Unlike almost every other LEGO game, the Wii U version is single-player only . The "Fixed" Versions (Switch, PS4, Xbox, PC)
For users seeking to play the Wii U version of LEGO City Undercover
The term "fixed" regarding this specific title originates from the early days of Wii U scene dumping and emulation. The initial releases of the game had copy protection and file structure quirks that caused issues when played on non-official hardware or loaded via Loadiine (a Wii U homebrew loading method).
: Some users report that later revisions of the game (marked as "Rev 1") contain internal bug fixes that resolved initial launch-day loading issues. Storage Capacity