Project Sandcastle (2020)
Corellium's Project Sandcastle ran Android on iPhone 7, 7 Plus, and 7th-gen iPod Touch using the checkm8 BootROM exploit and PongoOS. The project took over a year and involved many top iOS engineers.
Android booted on A10 devices with limited hardware support. GPU, audio, camera, and cellular were not functional.
Demonstrated that Apple's locked boot chain could be bypassed on checkm8-vulnerable chips, but only A11 and older.
Sandcastle relied on checkm8, a hardware exploit. The new iPhone 11 work uses a fully custom bootloader with zero Apple code, on a newer A13 chip that checkm8 doesn't cover.
