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  1. Tegra X1+Four Cortex-A57 cores, a Maxwell GPU and 4 GB of RAM.
  2. hekateStarts the boot with switchroot’s ARM Trusted Firmware and U-Boot.
  3. The loaderPuts the kernel in memory with an Apple device tree written for the Switch.
  4. XNUApple’s kernel, built from source, with about forty drivers for the Switch.
  5. iPadOS 26 and 27Apple’s own system, with its arm64e code translated for the A57.

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The hardware

The Switch OLED runs on NVIDIA’s Tegra X1+, a chip from 2019 with four ARM Cortex-A57 cores, a Maxwell GPU and 4 GB of RAM, driving a 7-inch 1280×720 OLED panel. iPadOS is told it’s running on a 9th-⁠generation iPad, the oldest iPad that runs iPadOS 27.

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Booting

hekate starts the boot the way it starts Linux or Android, using the firmware switchroot made for Linux on the Switch (ARM Trusted Firmware and U-Boot). From there, this project’s own loader puts the kernel in memory along with an Apple device tree, the hardware description XNU expects to find, written for the Switch. Then it jumps into the kernel. The Apple logo appears in hekate and stays in exactly the same place, pixel for pixel, through the loader and the kernel until iPadOS takes over the screen.

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The kernel

The kernel is XNU, built from the source Apple publishes, with this project’s changes on top. iPadOS 26 and 27 both run on xnu-12377, iPadOS 26’s kernel, because Apple hasn’t published 27’s kernel source yet. About forty drivers handle the Switch’s hardware: the SD card, display, touchscreen, Joy-Con, Wi-Fi, Bluetooth, audio, battery and charging, USB, sensors, the GPU and the video engines. They’re IOKit drivers like Apple’s, and they’re linked into the kernel. Apple’s own kernel extensions come from the iPadOS download and are linked in next to them, so iPadOS sees the same kernel interfaces it would on an iPad. There’s no Secure Enclave on the Switch. A stand-in answers iPadOS’s key store, and the Tegra’s own security engine does the AES and SHA work. Every driver runs on hardware interrupts and moves data with DMA, which leaves the CPU free for apps.

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Running arm64e code on older cores

iPadOS 26 and 27 are built for arm64e, the instruction set of Apple’s A12 and newer. It uses pointer authentication and newer atomic instructions, and the Cortex-A57 has neither. This project translates that code into instructions the A57 has:
  • Apple’s kernel extensions are rewritten once, when the kernel is built.
  • The shared library cache that every app loads is planned once per iPadOS release, on the Mac, and each page is rewritten as the kernel reads it in.
  • Every other program is translated as it loads.
The files on disk never change, so Apple’s signatures and the sealed system volume stay valid. Pointer authentication always succeeds, because nothing is ever signed. One cost is that arm64e apps can’t use a JIT, so JavaScript runs in its interpreter.

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Graphics

iPadOS draws everything with Metal. Here, metal2vulkan translates Metal’s shaders and API calls into Vulkan, and NVK, Mesa’s Vulkan driver for NVIDIA GPUs, compiles them for the Switch’s GPU. Underneath, a kernel driver built from Linux’s nouveau runs the GPU itself. The display shows Core Animation’s frames directly, with no extra copy, and a playing video can go on a hardware plane of its own. Compiling shaders on the console would make the first boot crawl. Instead, the image builder searches the iPadOS download for every shader it can find, translates and compiles them on the Mac, and puts the results into the image, so the shader cache is full before iOS boots for the first time. Video goes to the Tegra’s own engines: NVDEC decodes, NVENC encodes, NVJPG decodes JPEGs, and VIC converts, scales and rotates pictures. iPadOS’s video framework finds them through decoders and encoders this project adds.

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Storage, and why it needs a Mac

iPadOS lives on an APFS container on its own partition of the SD card. The system volume comes straight from Apple’s download, next to the Data and Preboot volumes and Apple’s cryptex images. Building that container takes macOS’s own APFS tools, which is why the image builder runs on a Mac and nowhere else. The installer on the Switch then copies the finished image onto the partition.