Nintendo Switch Online hasn’t even been out for a day and hackers have already found a way to upload new NES games to its existing library.
Nintendo Switch Online, a paid subscription service required to play most Switch games online starting today, also included other features like cloud backup saves and a downloadable library of 20 NES games. These NES games, which include stuff like Super Mario Bros. 3 and River City Ransom, come with a new online multiplayer component. Otherwise, they appear to function very much like their original versions, many of which recently appeared on the NES Classic. According to recent reports by hackers, both emulators work in a very similar way, which makes it possible for people to add their own NES games to the Switch Online’s library.
— kapu | the Gay. (@KapuccinoHeck) September 19, 2018
Overnight, a Switch hacker who goes by DevRin uploaded a video to YouTube that appeared to show the opening of Battletoads running on the new Switch Online NES games app. This inspired a modder who goes by KapuccinoHeck to investigate further in conjunction with two others, OatmealDome and Master_F0x.
In a series of tweets today, KapuccinoHeck shared their findings, claiming the Switch Online app that houses these NES games treats them like plain .nes files, with a database file that lists in plaintext all of the other compatible NES games. In other words, there wasn’t a whole lot standing in the way of people hacking the emulator app and adding their own new NES games to it. “Here have the NES Classic emulator and a few ROMs lol go wild,” is how KapuccinoHeck described it in one tweet.
They also shared a video of the opening of Kirby’s Adventure, which is not currently one of the NES games included with the launch of Switch Online; in the video, it appeared to be running on the console via a ROM hidden under the River City Ransom box art section. Since then, DevRin has posted a video of Battletoads actually being played on the Switch from within the app.
It isn’t that easy to get these games onto the Switch. In an email, KapuccinoHeck told Kotaku the NES games can only be added to hacked Switches, which remains a complex undertaking and carries the constant threat of having your account banned by Nintendo. “I would highly advise against anyone else doing it as I’ve been told there’s a lot of data from the app being sent to Nintendo and that it has a fair few legitimacy checks that occur at random,” they said.
In the meantime, KapuccinoHeck doesn’t think the vulnerabilities in the Switch Online NES library will be easy for the company to quickly patch out. When asked for comment on the matter, a spokesperson for Nintendo of America told Kotaku, “We have nothing to announce on this topic.”