I bench tested Black Widow's new electronics last week, and only three of the four channels fired. I went through the connections and they seemed OK, so I set up another test, moving the unburned match to another channel. This time, the altimeter showed that channel with no continuity, confirming that it was a bad match.
With a good match on that channel, all four channels fired just fine. Onward!
Video of test, showing the BlueRaven app: https://www.youtube.com/watch?v=NTlh-1UFDhk