Setup OSDev Environment on macOS

Why OSDev on macOS works (if you stop fighting defaults) The failure mode is always the same: you follow an OSDev tutorial, hit make, and end up with a binary that either won’t boot, won’t link, or isn’t even in the format your bootloader expects. macOS is a great editor and workflow environment. But it is a terrible default build target for classic OSDev. This guide builds a layered mental model for the “why”, then gives three setups (from lightest to heaviest) that I’ve used successfully: a cross-toolchain on macOS, a Docker build container, and a Linux VM via Lima. The two hard constraints (the stack you can’t ignore) 1) CPU architecture: aarch64 vs x86 Modern Macs (M1/M2/M3/M4) are aarch64 (ARM64) machines. Most OSDev examples, bootloaders, and “hello kernel” walkthroughs targets i686/x86_64. What breaks: Native clang/ld produce ARM machine code by default. Why it matters: An x86 emulator (or real x86 hardware) can’t execute ARM opcodes. If your kernel is the wrong ISA, you won’t g