Hi guys, I've upgraded my old Mac Pro tonight but I cannot get it to boot. It has the 2,1 firmware and running El Cap on a new SSD. Everything was working great with the old HD 5770 when I powered the rig down. I did the pixlas mod and I rechecked the pinout twice with a multimeter to make sure I did it right. I am plugging via HDMI and going thru DVI with an adapter did nothing. Do I need to buy a display port to HDMI adapter?