What was done
A CLI plus GTK4 GUI replaces the Windows-only driver: lighting, battery, music sync and remapping, with the protocol committed as documentation.
ajazzctl is an unofficial Linux tool for the AJAZZ AK820 Max Plus tri-mode RGB keyboard. Its commits carry Claude Opus 5.5 as co-author.
How it was done
The config protocol of the Windows vendor driver was reverse engineered and is documented in the protocol notes in the docs folder. Typing is untouched because the kernel HID driver keeps handling the keys, and ajazzctl only opens the separate vendor configuration interface, gated by a udev rule that exposes only interface 0 so no program can read keystrokes. A simulated keyboard mode lets the CLI and GUI be developed without hardware.
Results
The feature table is hardware-verified: detection over USB and the 2.4 GHz receiver, battery and charge state, 16 lighting effects with brightness, speed, direction and colours, an on-keyboard custom per-key RGB mode with a paint UI and live preview, music sync driven by the spectrum, and lights preserved through reboots. Key remapping works experimental with a target-verification gap recorded, firmware updates are intentionally not built, and installation ships a makepkg package with a udev rule.