The H Plus, is one of the most solid drones I have ever owned. When it first came out, I got mine and quickly found it was nothing like the 480. In addition there was many aspects that we found out (by trial and error) on our own. I have never tried to fly without camera so I never came up against this but it would seem that this is yet another aspect of the H Plus that is different from the 480 in that; some functions may not be operable without camera therefore, operations without camera is inadvisable as what you've experienced may not be the only aspect that doesn't work without one.
Curious; so I take it you bout a used H Plus with no camera?