Switch is in the correct position.

Hooked up as you've recommended, and even swapped MISO and CS pins to the other pins on the ProMicro, just to test.

Current connections:
SR - ProMicro
MISO - D2 (RX)
5V - VCC
SCK - B1 (SCK)
CS - D3 (TX)
GND - GND


If I flip the switch, all 24 buttons show as pressed. If I disconnect the MISO/CS pins, all 24 buttons show as pressed. If I set the wrong pins in mmjoy2, all 24 buttons show as pressed. If connected and configured correctly and I pull one of the 24 button pins on the SR to ground, no buttons show as pressed in mmjoy2.

Banging my head against the wall here.