Switch the board in configuration mode by sending the sysex "F0 77 77 78 08 F7" The board will disconnect and connect again in serial mode. You should see the led blinking very quickly.
But the actual sequence is "F0 77 77 78 06 08 F7". It is correct in the readme.md, but misses the 06 in the documentation.
Section 4.3.1 of the manual at https://github.com/TheKikGen/USBMidiKliK4x4/wiki/UMK4x4-V2.5-User-Manual reads:
But the actual sequence is "F0 77 77 78 06 08 F7". It is correct in the
readme.md
, but misses the 06 in the documentation.