Fitting USB bluetooth dongle to internal mini-USB connector on an iBook G4

Hello,

Ive been working on this hack today, and have all the neccessary parts to make it happen. BUT I meassure VDC+ on the standard USB2.0 ports to be +5V, while the internal mini-USB connector on the motherboard carries +3.3V. Anyone care to think out aloud if USB dongles designed for a standard 5V USB port can operate on 3.3V? Is the USB1.0/1.1 standard by any chance spec'ed at 3.3V? I've tried looking it up, but nowadays its all USB2.0...