Unfortunately I dont have another powered usb hub... This is brand new and costed me $30
if I just plug the hub to the usb ports it doestn power the pi. I think that the pi have some diodes to prevent current coming in from the usb ports (I dont know anything about electronics, I read this on a forum). If I use a usb-microusb cable from the hub to the pi's power connector, the pi starts, but it flickers the same way I described before...
What I dont understand is, if the pi has something to prevent (I think they are diodes) current coming in from the usb ports (I tried this as it doesnt power the pi if I just connect the powered usb hub to the pi's usb port), why should feedback power from the powered hub affect its behavior? Because if I dont power the hub (I use it as a normal hub without powering to the electricity) the hub works fine with a usb stick.
Is there any walkaround this? Is there any way I can meassure if the usb hub is sending feedback power (maybe with a voltmeter, which pins should I check?)? If the problem is the feedback power from the hub to the pi, is there any walkaround so I can use this hub?