S2Arm rebuilds Switch games for iPhone, with one app holding the library

An iPhone can end up with a Switch library inside a single app. The part worth understanding happens before you tap Play.

S2Arm’s README describes static rewriting of a game’s ARM64 code so it can execute on the Apple device’s processor. Graphics calls go to Metal through a translation layer, and a native host supplies system services. The work moves into a build stage rather than asking a CPU emulator to do that translation during play.

One app contains the imported library. That means another game does not consume another developer-account app slot, a useful distinction on an iPhone where signing can become a hobby all by itself. Collecting games is already enough paperwork without collecting signed app shells too.

The README says “Bring your own games.” The open-source project uses Apache-2.0 and requires your own game files and keys. It has graphical launchers for Mac and Windows. Apple silicon Macs running macOS 15 or later can build and play locally; iPhone and iPad support starts with iOS and iPadOS 18. The Mac route for an iPhone build needs Xcode and an Apple ID. Android and HarmonyOS are listed as future work.

The project reports surveying 211 games with a 95% first-try build success rate. That is a build figure. A program compiling successfully does not tell you whether its last boss, cutscenes or save system behave correctly. The source also reports thousands of device test runs, which is useful context without turning the build percentage into a promise about every title.

Its published timing table gives the size of three example jobs on a 16 GB M3 MacBook Air. A 23.5 GB action RPG took 6.4 minutes for a cold iPhone build, a 12 GB life sim took 8.6, and a 17.5 GB open-world game took 34. The last example had far more shaders. Game size alone would have been a pretty lousy stopwatch.

The thermal caveat deserves equal billing. For one Switch 2 game on an iPhone 17 Pro Max, the project reports 60 frames per second while cool and 37 to 43 after sustained load heats it up. That is a considerable drop even though the port runs natively. The phone still lives in the physical world (inconvenient little detail), where doing work produces heat.

There are firm compatibility exclusions. AArch64 is supported; 32-bit ARM games and games requiring a 36-bit address space are outside the stated boundary. The README also warns that the release’s new app identifier means beta saves do not transfer automatically. A successful build is an especially bad moment to discover the save belonged to the old app.

Native translation could make more portable game experiments practical, but the project’s own table leaves plenty for a buyer to check: the specific title, device, build and length of play. A library that fits in one signing slot still has to fit inside the phone’s cooling budget.

One slot. Still a hot pocket.