Flashing a Liatris Microcontroller

Last year I built myself a Lily58 split keyboard after already having built a crkbd before. The fact that I never really finished the software is apparent by my local qmk_firmware branch still being called aurora-lily58-test . For the Lily58 I used a Liatris Microcontroller , which is pin-compatible with the Pro Micro . Because I never finished writing any documentation for the keyboard,…