We can put the phone in developer mode, so we can run test applications with the proprietary graphics driver and inject our own code with LD_PRELOAD , allowing us to inspect the graphics memory prepared by the proprietary driver and “passively” reverse-engineer the hardware. With drm-shim , unmodified userspace drivers think they’re running against real hardware – including Valhall hardware. With these fixes, we finally see our first passing test, running on real hardware, with data structures prepared by our open source Mesa driver and shaders compiled by our Valhall compiler.