I should have mentioned I have the Gopro 4 black with the H4-3D and have not updated to 3.08. I might have not waited long enough will try again. Is the an advantage to not using the interference board?Not sure. I can power mine on any time, before or after powering the phantom. I think its best turning the go pro on then the phantom to minimise strain on the H33D.
But to help you out...
I have 3.08 firmware on the non upgraded vision plus.
Latest firmware on Gopro 3+BE.
I use the rear hero port and NOT the side usb.
I don't use the interference board.
I run 640x480@15fps for FPV.
And be a little patient.
The gopro takes about 30 seconds to appear sometimes.