Solution:
Manually force an update via the + menu as described above. If still no luck, your cartridge may be from a different region. Updates are region-free, but you may need to change your Switch’s region temporarily.

No external computer, RAR extraction, or “exclusive” source is required.

To understand the danger of fake or pirated updates, you must first know what the official update does.

Shortly after the Arkham Trilogy launched on Switch, players reported performance issues, including frame rate drops, texture pop-in, and audio glitches, particularly in Arkham City. Warner Bros. Games and Turn Me Up Games (the porting studio) released several patches:

This update weighs approximately 1.8 GB (downloadable directly from Nintendo’s servers). It is not available as a standalone RAR file; it’s delivered via the Switch’s system software when you connect to the internet.

Solution:

Even if the NSP appears to install, patched updates from unknown groups may have improperly merged code, leading to game-breaking bugs (e.g., Catwoman’s missions not triggering).