Amúgy az a szép h. ez az Y kábelt a HIVATALOS szabványban tiltott:
https://en.wikipedia.org/wiki/USB#Power
Some devices, such as high-speed external disk drives, require more than 500 mA of current[88] and therefore may have power issues if powered from just one USB 2.0 port: erratic function, failure to function, or overloading/damaging the port. Such devices may come with an external power source or a Y-shaped cable that has two USB connectors (one for power and data, the other for power only) to plug into a computer. With such a cable, a device can draw power from two USB ports simultaneously.[89] However, USB compliance specification states that "use of a 'Y' cable (a cable with two A-plugs) is prohibited on any USB peripheral", meaning that "if a USB peripheral requires more power than allowed by the USB specification to which it is designed, then it must be self-powered."[90]
--
WP8.x kritika: http://goo.gl/udShvC