I just read a post on the Pro Video Coalition:
How will P2 operators who want to upgrade to the Hero 4 handle this?
"I've just confirmed with a GoPro product manager that the Video Out signal on the bus port on the back of the HERO4 WILL NOT provide a video-out signal for the Zenmuse H3-2D gimbal, nor the early relased v1 of the H3-3D gimbals. You must use an FPV connector to the USB port on the side of the GoPro to get an FPV signal out. At this time, there is no word of a firmware update from GoPro to resolve this."
How will P2 operators who want to upgrade to the Hero 4 handle this?