A reimplementation of the 3DS mic sysmodule written in zig.
The only dependency is zig 0.16.0 (already available in the repo flake if you use nix)
Run zig build; it'll download dependencies and build zitrus tools first, afterwards rebuilds are instantaneous.
You should see mic.cxi in zig-out/bin alongside mic.elf.
Copy mic.cxi to /luma/sysmodules/0004013000002002.cxi in your sd card.
...
Profit?
All credits go to 3dbrew and GBATEK as I could not do this without all the available documentation.