The first batch of Kay65 (Rev. 1) does not support the use of a daughterboard via JST cable, despite a JST header footprint being present. This is due to a miscommunication with our factory. Please only use this PCB for boards with on-board USB connectors (Mini-USB and Type-C).
1 Nov 2022 Update: Firmware update to fix the reversed Caps Lock LED indicator (Light on when Caps Lock off).