HoloLens USB APIs

Can anybody here help point the way to how to solve this USB problem? I'm running this bit of code on a PC and also a HoloLens:

       string aqs = UsbDevice.GetDeviceSelector(0x03E7, 0x2150);
        var info = await DeviceInformation.FindAllAsync(aqs);
        foreach (DeviceInformation di in info)
        {
            Debug.WriteLine("found " + di.Id + " => " + di.Name);
        }

Pretty simple, right?

It detects the device correctly on the PC but not on the HoloLens. Why? I'm not that familiar with the USB APIs, but I thought the whole point of UWP was that the code would run on any Win10 platform? Am I missing a driver on the HoloLens, perhaps? Or does HoloLens just not support external USB devices?