The first firmware update is out. This release fixes the tuning of the internal sound, which was 270 cent sharp. Thanks @rdjvonk for reporting.
To update the firmware, connect the Striso board to a computer with the square button pressed, now it should have a blinking red light and should appear as a flash drive. The current firmware version can be found in INFO_FW.TXT.
For this release first update the bootloader by copying strisoboard_v2_bootloader_v1.1.2-0-g32b1c18.uf2 to the Striso board. The Striso board light should turn blue momentarily and start blinking red again.
Now copy the firmware update striso_control_2021-03-05_v2.0.2-0-gc9cfde1.uf2.
Please let me know if it works.