ZMK Firmware¶

Corne (42-key split) keyboard firmware. The configs, keymap, OLED patches, layouts and build logic live in semi710/zmk-config, documented at zmk.semi.sh - ndots consumes it as a flake input and gets the packages for free:

# flake.nix
inputs.zmk-config.url = "github:semi710/zmk-config";

outputs = inputs:
  inputs.nix-wire.mkFlake { inherit inputs; } {
    imports = [ inputs.zmk-config.flakeModules.default ];
  };

The flake module adds packages.zmk / packages.zmk-flash (default keyboard) and packages.zmk-<name> for every keyboard the repo carries. Layouts, layers and the OLED setup are all on zmk.semi.sh - this page only covers the ndots build/flash angle.

Build¶

just zmk-build    # nix build .#zmk -> result/zmk_{left,right}.uf2
nix run .#zmk-flash    # interactive flash on a Linux host

CI in zmk-config builds every keyboard on push; ndots' cache workflow builds packages.zmk on all platforms and pushes it to cachix.

just zmk    # waits for the latest zmk-config CI run, downloads firmware to zmk/out/

Flash (nice!nano v2)¶

Double-tap the reset button - the half mounts as a USB drive (NICENANO)
Copy the matching .uf2 from result/ (local build) or zmk/out/ (CI):
- left half -> zmk_left.uf2
- right half -> zmk_right.uf2
The half reboots automatically once the file is copied

jp-mbp cannot flash

The work MDM on jp-mbp blocks mounting the bootloader volume (Disk Arbitration veto), and even raw mount_msdos fails - the FAT kext is rejected at signature check. Flash from a Linux host instead:

ssh niksingh710@mach 'rm -f ~/zmk_*.uf2'  # old copies are read-only (nix store perms carried by scp)
scp result/zmk_*.uf2 niksingh710@mach:~
# plug the half into mach, double-tap reset, then on mach:
cp ~/zmk_left.uf2 /run/media/$USER/NICENANO/    # copy = flash

The halves must run matching firmware versions to talk to each other - flash both back-to-back and expect the keyboard dead in between.

ZMK Studio¶

Both halves build with ZMK Studio enabled, so the keymap can be tweaked live over USB with ZMK Studio without reflashing. The unlock combo is pressing TAB + Q together.

Note

Studio edits are runtime-only. Lasting changes go in keyboards/corne/corne.keymap in zmk-config.