Got my probe a while ago and finally set it up today. Have a 2.4d board. Plugged it into the empty socket, ran the cord through the hole in the bottom of the electronics box at the back of the Nomad, as shown in the photo.
Grounded to the metal plate the electronics box is mounted to (see second photo).
With machine on, probe LED is green, and turns red when touched with the alligator clip. So far so good.
Next, I updated to grbl 1.1 and CM4. CM4 quasi-automatically sent the homing parameters to the machine. It now homes, but when measuring tool length on the Nomad’s tool length measurer, the machine stops about halfway down and says “ERROR (4): Probing Cycle Failed”.