I reflashed the P12S board with firmware 3.4b and then all outputs were dead. I reflashed again just incase I made a mistake but still all dead.
Strangely, the ASIC version numbers on the System Information web page were all zeros.
So I flashed 3.4 instead and now all outputs work. I am guessing that ten years ago when I originally flashed 3.4 I must not have programmed the second ASIC. Unfortunately, 3.4 does not support two full universes per output with 2811 pixels.
However, I would really like to get 3.4b working. I sent Ed an email but I will be surprised if he replies.
This could hopefully help. Can't remember what I did, but mine is running two universes no problem. This should be everything I used to update my J1Sys controllers.