I just did follow the instructions (oopsi didn't see that one!) but still, I have the same result. Nothing happens, no image or visible sign of activity whatsoever.
I just installed the same firmware, opened Isadora and added an OpenNI Tracker, and I had a depth image without any issues.
This is with an Intel Realsense D435 (make sure you have that model) and the following software:
1) macOS Catalina 10.15.6
2) OpenNI Tracker 0.9.8b2 -- available on our plugins page.
3) Intel Realsense Firmware (from file Signed_Image_UVC_5_12_7_100.bin)
Does that match your setup?