I use a (genuine) Apple iPhone PSU to power my RasPi. This is rated at 1A. I recently got a powered 4 port USB hub which has a 2A PSU. But I was shocked to discover that with the Apple PSU disconnected, the RasPi powered up as soon as I plugged in the USB cable from the hub.
My question is if I have both the USB hub connected and have the Apple PSU plugged in, what is RasPi using as its power source? Can I stop RAsPi from using the hub as a power source? I want the RasPi to just use the Apple PSU and leave the hub PSU to power just the hub peripherals.
Thanks for any advice.