I have a weird FireWire issue I haven’t seen before. FireWire disks are not mounting under either Sierra, ElCap or Yosemite. Yet I am able to option boot from the FireWire disk and after it loads still can’t mount any other FireWire disks. Profiler shows error message that it can’t list the devices. Yosemite console shows an error message that FireWire bus may be unstable. I have tried SMC and PRAM reset to no avail. Is it hardware or software failure? Because it boots from FireWire it would indicate that the ports are working so not clear. I don’t really care about FireWire anymore but still it has its uses and it would be nice if it worked. It may be relevant that I recently got a replacement logic board and have done the 4,1 to 5,1 firmware upgrade. But I hadn’t heard that would cause a FireWire issue. Stumped on this one.