. It allows you to drag and drop the base game, its update, and all DLCs to create a "multipack". Switch Army Knife (SAK)
Have a specific game you want to patch? Check the "ROM Hacking" subreddit or GBAtemp's Switch forum for dedicated threads. nintendo switch rom patcher
ROM patching is a "delta" process—the patch contains only the differences between the original game and the modified version. nintendo switch rom patcher