[MinnowBoard] Minnowboard Max - power from USB port (questions)

[Chris Brookes]

I saw the wiki entry on how a powered USB device might wind up pushing juice in to the Minnowboard Max due to the lack of a diode in the design. I have seen this happen myself and the Minnowboard, at least for the few  minutes I had it in this state, did not appear to suffer and did seem to work properly. Interestingly, in this state with power from 2 sources, if I unplugged either it would continue to operate as if nothing odd had happened. It was sort of like having dual independent PSU’s.

What is the risk in leaving it in this state? It’s obviously out of spec, not a good idea generally and so on, but what could happen, what probably would happen, and what (if anything?) definitely will happen if it’s left to operate in this state for any period of time?

Just curious…

Chris