Ergohaven RMK Firmware

RMK BLE split firmware for Ergohaven keyboards and trackballs (nRF52840).

Supported Devices

Keyboards (BLE split)

Keyboard	Layout	Encoders	Trackball
K:03	5×6 + 5 thumb	3+3	—
K:04	5×6 + 5 thumb	1+1	—
K:04 Qube	5×6 + 5 thumb	1+1	Qube dongle + ST7789
K:04 Micro	3×5 + 3 thumb	1+1	—
Imperial44	4×6 + 3 thumb	1+1	—
OP36	3×5 + 3 thumb	—	—
OP36 Qube	3×5 + 3 thumb	—	Qube dongle + ST7789
Velvet	4×6 + 5 thumb	—	—
Velvet UI	4×6 + 5 thumb	—	PMW3610

Trackballs (standalone BLE)

Device	Buttons	Modes
Trackball Royale	6	Normal, Scroll, Sniper, Adjust
Trackball Mini v3.1	4	Normal, Scroll, Sniper, Adjust
Trackball Mini v3.0	2	Normal, Scroll, Sniper, Adjust

Tools

Tool	Description
settings_reset	Erases keymap and BLE bonds, resets to bootloader

Building

cd keyboards/k03
cargo build --release --bin central
cargo build --release --bin peripheral

Current K:04/OP36 regression matrix:

./scripts/build_k04_matrix.sh

Flashing

1. Put device into bootloader (double-tap reset)
2. Copy .uf2 file to the mounted USB drive
3. For split keyboards: flash central and peripheral separately

Settings Reset

Flash settings_reset.uf2 to erase all saved keymap/BLE data, then re-flash keyboard firmware.

CI

Every push builds all devices in parallel via GitHub Actions. UF2 artifacts available as build downloads.

RMK Version

Based on RMK 0.8.2 with nRF52840 BLE support.

The root rmk, rmk-macro, rmk-types, and rmk-config crates are the source of truth for firmware targets in this repository. K:04 selects one of two explicitly named split BLE backends through [split].backend:

• common: ordinary no-Qube keyboards/k04 halves.
• qube: keyboards/k04_qube dongle/halves connection path.