[SpecialistK]

> I wonder, though, how difficult would it be to replace older versions of Darwin (the open-source BSD and Mach layers of macOS) with updated code while ensuring the proprietary layers running on top of Darwin still work?

This is something I've thought about a lot and would love to see pursued.

We know that the XNU kernel from Snow Leopard still lists PPC (https://github.com/apple-oss-distributions/xnu/tree/xnu-1504...) but it probably won't be easy to build and replace a 10.5 kernel with.

The Hackintosh community did a lot of kernel hacking and custom kexts early in the Intel transition. It would be great if those people pivoted to PPC backporting or sharing their experiences once Apple drops x86 support in the near future.

[saagarjha]

A lot of code written these days basically assumes little endian so this might be more difficult than just a recompile and patch up unfortunately :(