Keep your base game and update files separate. Do not attempt to permanently merge or "hard-patch" an .nsp update into a base .xci file using unreliable third-party tools.
After installing the ROM, load the game. If the title screen has a large pink crystal on the right side labeled “Chapter 9,” you have the DLC. If you only see Chapters 1-8, you are missing the update.
Even with a perfectly patched ROM, the game will stutter and lag if your emulator is not set up correctly. Here’s how to configure Yuzu or Ryujinx for a smooth 60 FPS experience:
Before diving into the legal aspects, it’s fair to examine why gamers look for these fixes. The need arises from technical friction between the game software, the console hardware, and emulation software.
The definitive solution to fixing the involves utilizing targeted patching tools or updated file versions to bypass standard emulator crashes and cryptographic verification errors. Why Emulators Crash on Celeste Switch ROMs
Interacting with this "fixes" your access to the original 8-bit version of the game, which is then playable from the main menu.