Ok, the classic question: Can we charge Aurora 2 using mini usb cable connecting to a 2A power bank? I know most sites even the company site recommend using the power adapter but it's rather troublesome to carry it around. I suppose ainol does not recommend via usb port because they produces 500mAh power which is insufficient or very slow to charge the unit. Yoobao 11200mAh power bank has 2 outlet, 1A and 2A which could charge 2 devices at the same time. I can then carry one of this unit to charge both my Bold 9780 and Aurora 2. Any feedback?