"Chris, Thanks! But I'm actually okay with it. I have no need to power the board from the output pins (yet..) And we have waited long enough for the boards, I just want to fly this thing already :)"

"Alright, I've tried that, and, well, it's the same story when using output 3 or any other channel. The juice just won't go from output to input rail, but happily flows in reverse direction."

"I have a separate UBEC and I'm connecting it's output to a free channel on a rail."

"My board behaves the same way. With the jumper on, I'm only getting 1.32V on the input rail when powered from the output rail. But, strangely enough, when powered from the input rail and with the jumper on, there are full 5V on the output…"

"I believe it's this one."

"Great to know, thanks! Ordered one a week ago, waiting for it to arrive.Is there any space between the frame boards to put, for example, a power distribution board there?"