Problems upgrading the BBB Angstrom OS - some obvious questions

I don’t know the details of the USB spec offhand, but will using a powered hub actually guarantee that you can get more than 0.5 A? I would think the if USB is limited to 0.5A then that’s all you’ll get, period, and that you would have to supply power to the BB directly through it’s power input, not via USB, to make sure you get more. Or does the spec promise that you can get “at least” 0.5 A?