Keebart ZMK Firmware

This repository contains the ZMK firmware configuration for Keebart wireless split keyboards. It includes board definitions, default keymaps, ZMK Studio support, Sharp Memory-in-Pixel display support, RGB underglow, and GitHub Actions firmware builds.

• Maintainer: Keebart
• Firmware: ZMK
• Miryoku firmware: Keebart/miryoku_zmk
• Online keymap editor: ZMK Keymap Editor
• Runtime editor: ZMK Studio

Supported keyboards

Keyboard	Layout	Board targets	Bluetooth name
Corne Choc Pro BT	6-column	corne_choc_pro_left, corne_choc_pro_right	Corne Choc BT
Corne Choc Pro BT 5-Col	5-column	corne_choc_pro_5col_left, corne_choc_pro_5col_right	Corne Choc BT
Piantor Pro BT	6-column	piantor_pro_bt_left, piantor_pro_bt_right	Piantor Pro BT
Piantor Pro BT 5-Col	5-column	piantor_pro_bt_5col_left, piantor_pro_bt_5col_right	Piantor Pro BT
Sofle Choc Pro BT	6-column	sofle_choc_pro_left, sofle_choc_pro_right	Sofle Choc BT

The shortened Bluetooth names fit ZMK's 16-character device-name limit while making wireless models identifiable in the host's Bluetooth menu.

Firmware variants

Corne and Piantor have separate 6-column and 5-column firmware targets. The 6-column targets retain the standard keymaps. Targets ending in _5col use a compact keymap designed specifically for boards without the outer columns.

Separate firmware is intentional. ZMK Studio can switch between physical layouts in one firmware, but it stores one runtime keymap rather than two independent defaults. Separate targets also give the ZMK Keymap Editor one unambiguous source keymap and geometry for each keyboard variant.

Select matching firmware for both halves. Do not mix a regular target with an _5col target.

Default 5-column keymap

The compact keymap uses home-row modifiers and thumb keys that tap common keys or hold dedicated layers.

Home-row modifiers

Tap a home-row key to type its letter. Hold it to use its modifier.

Key	Hold action	Key	Hold action
A	Left GUI	J	Right Shift
S	Left Alt	K	Right Ctrl
D	Left Ctrl	L	Right Alt
F	Left Shift	'	Right GUI

The mod-taps use a 200 ms tapping term and ZMK's tap-preferred flavor to avoid turning ordinary same-hand typing rolls into modifiers.

Thumb keys

Tap	Hold
Esc	Media layer
Space	Navigation layer
Tab	Function layer
Enter	Symbol layer
Backspace	Number layer
Delete	Adjust layer

Layers

Layer	Main contents
QWERTY	Letters, punctuation, home-row modifiers, and layer-tap thumbs
NAV	Arrow keys, Home, End, Page Up/Down, Insert, Caps Lock, and modifiers
MEDIA	Playback, volume, and RGB controls including hue down/up
NUM	Numpad-style digits, brackets, semicolon, equals, backslash, and grave
SYM	Braces, parentheses, operators, colon, and shifted symbols
FUN	F1-F12, Print Screen, Scroll Lock, Pause, and modifiers
ADJUST	Bluetooth profiles, RGB controls, reset, bootloader, and Studio unlock

To unlock ZMK Studio on a 5-column build, hold the Delete thumb key and press C. Reset and bootloader are on Z and X on the same layer.

The source files are:

• config/corne_choc_pro_5col.keymap
• config/piantor_pro_bt_5col.keymap

Matching board-default copies are kept under boards/arm/*_5col/.

Miryoku firmware

Alternative firmware using the Miryoku layout is maintained in Keebart/miryoku_zmk. Its GitHub Actions workflows build Miryoku firmware for the standard Corne Choc Pro BT, Piantor Pro BT, and Sofle Choc Pro BT targets.

The Miryoku repository loads this repository as an external ZMK module. Board definitions and the sharp_mip display shield remain here, while Miryoku owns the keymap and physical mappings. Its keyboard workflows select sharp_mip as an extra shield, so the custom display remains available in Miryoku firmware.

Run the matching workflow from the Miryoku repository's Actions tab and flash the generated left and right firmware files to their corresponding halves. Miryoku firmware is an alternative to the default keymaps built by this repository; it is not an additional runtime-selectable keymap.

Building firmware

The GitHub Actions workflow builds all targets on every push and pull request. It can also be started manually from the repository's Actions tab. Download the merged firmware artifact after the build finishes.

The build matrix is defined in build.yaml. Normal firmware uses the custom sharp_mip shield on every keyboard. Corne and Piantor use its default orientation; Sofle enables the 180-degree rotation in its board configuration. The central, left-side builds include ZMK Studio support.

For a local build, first create a normal ZMK west workspace using the manifest in config/west.yml. From the workspace root, run a command such as:

west build -s zmk/app -d build/corne-5col-left \
  -b corne_choc_pro_5col_left \
  -S studio-rpc-usb-uart -- \
  -DZMK_CONFIG=/path/to/zmk-config/config \
  -DZMK_EXTRA_MODULES=/path/to/zmk-config \
  -DSHIELD=sharp_mip \
  -DCONFIG_ZMK_STUDIO=y

Change the board target as required. The resulting firmware is written to build/corne-5col-left/zephyr/zmk.uf2.

Configuration settings

User-adjustable firmware settings belong in the matching config/*.conf file. This includes the keyboard name, power management, RGB defaults, display idle behavior, and an optional pointing setting. The files under boards/ describe the keyboard hardware and its internal defaults; normal users should not edit them.

Flashing

The halves use different firmware because the left half is the central side and the right half is the peripheral side.

1. Download or build the firmware package.
2. Enter the bootloader on the right half and copy its matching right-side UF2 file to the USB mass-storage device.
3. Enter the bootloader on the left half and copy its matching left-side UF2 file.
4. Reconnect the keyboard and pair it with the host if necessary.

Enter the bootloader by double-pressing the physical reset button, or use the bootloader key in the active keymap. On the 5-column keymap, hold Delete and press X.

Resetting saved settings

The build artifact also contains settings_reset firmware for the standard Corne, Piantor, and Sofle targets. Use it when split pairing or stored settings prevent normal operation:

The standard Corne and Piantor settings-reset files can also be used before reflashing their matching 5-column firmware because the hardware is the same.

1. Flash the appropriate settings-reset firmware to a half.
2. Allow it to boot and clear the saved settings.
3. Immediately flash the normal firmware for that half again.
4. Repeat for the other half when resetting split pairing.

Settings-reset firmware is temporary and is not a usable keyboard firmware.

Editing keymaps

ZMK Keymap Editor

The ZMK Keymap Editor edits the source .keymap files in this repository. Choose the file matching the keyboard and column count. The accompanying JSON files in config/ provide the correct visual geometry.

Editing and committing a source keymap triggers a new GitHub Actions build. This is the recommended workflow for maintaining and distributing defaults.

ZMK Studio

ZMK Studio edits the runtime keymap stored on the keyboard. Connect the left half directly by USB, unlock Studio from the keymap, and select the device in the browser.

Studio changes do not update the .keymap source file. Conversely, flashing new firmware may not replace a Studio-edited keymap because the runtime state is saved. Use Restore Stock Settings in Studio after changing between 6-column and 5-column firmware or whenever the compiled default should be loaded again.

Power management

Deep sleep is enabled on every half. The keyboard enters deep sleep after one hour (3600000 ms) without activity and wakes when a key is pressed. The long timeout avoids the keyboard appearing to sleep during normal breaks while still conserving battery during extended inactivity. Change these settings in the matching config/*.conf file.

RGB controls

RGB underglow is enabled with a conservative maximum brightness. On the 5-column keymap, hold Esc for the Media layer:

• Q: hue down (RGB_HUD)
• W: hue up (RGB_HUI)
• E / R: saturation down/up
• T: cycle effect

Brightness and toggle controls are on the bottom row of the same layer. The Adjust layer also contains the complete RGB control set for testing.

Rotary encoders

Corne Choc Pro supports four encoder definitions:

1. Volume down/up
2. Page Up/Down
3. Previous/next media track
4. Volume down/up

Sofle Choc Pro uses one encoder for volume and the other for previous/next media track. The encoder actions are available on its default, Lower, and Raise layers.