Download the firmware

For a blue-gray original PCB:

sonatina_cisne_rev1_vial.hex

For a black replacement PCB:

sonatina_cisne_rev2_vial.hex

<aside> 💡

Regarding QMK, it's currently in preparation.

</aside>

Install and open QMK Toolbox

https://qmk.fm/toolbox

Put the PCB into firmware update mode