The original Duo now runs iOS, and it’s not from Apple

For those in the know, the iPhone Duo is not the first foldable named “Duo.” Microsoft was first to launch the Surface Duo six years before Apple. Then in 2021, the Microsoft Surface Duo 2 was launched, and five years later, someone managed to run iOS 26 on it.

Developer SmuOS shared their Surface Duo 2 that they had been using for testing with Windows Central. The phone, despite its cracked display, is running iOS 26.5.2, but it thinks it’s the iPhone 17 Pro Max. That’s because the developer used the official iPhone 17 Pro Max restore image.

Even so, most menus seem to scale just fine as if they were running on the new iPhone Duo or an iPad. The Settings app shows a sidebar on the left and expanded options taking the rest of the screen space.

The Phone app is where the scaling fails. Because of the bezel in the middle of the Surface Duo 2, the 2,5, and 8 buttons are completely hidden. That’s true for other apps as well that have notifications or text in the centre. The touchscreen works just fine, though the OS runs at a crisp 37 FPS.

SmuOS is not stopping here. The developer has plans to make the Surface Pen work as an Apple Pencil, which is interesting since Apple just added that support for the iPhone Duo with the latest iOS update. Speaking of which, SmuOS also wants to port the iPhone Duo’s iOS 27 build to his Surface Duo 2.