I have been having difficulties getting GPS lock since adding fbosd. It took a long time when I had just one TX but when I added a second, it couldn't lock at all (Why two TX? read this). After a lot of experimentation and debug going nowhere, I read on another forum that adding a toroid to the GPS wire helps. Not enough lead on the stock gps wire so I tried adding it to the little tap you solder in during install and it works phenomenally. Now I get lock before the craft has finished warm up. You can see the toroid below with the five turns of the GPS wire around it at the top of the cavity (I mounted the fbosd and minimosd below the PCB on either side of the battery).