I have installed Windows 8.1 through bootcamp. I have to plug in a device that implements the USB 2.0 interface, however, my MBP does not have any USB 2.0 ports, only 3.0.

I know that theoretically USB 3.0 is backwards compatible, but not really. My device is not recognized at all if I plug it in a USB 3.0 port.

I need a way to force the USB 3.0 ports on my MBP to work as USB 2.0. I tried to install different drivers for xHCI with no success. I also tried with an USB 2.0 extension cord with no luck. Some other laptops can change the USB 3.0 ports speed from BIOS, but again, my MBP does not have a BIOS.

What can I do?

  • What kind of device is this? I've almost never heard of this happening. – Journeyman Geek Oct 12 '15 at 12:41
  • It's a car diagnostic device. – Alin Roman Oct 12 '15 at 12:43
  • Try using an USB hub. – duenni Oct 12 '15 at 12:46
  • If it were PC hardware, you'd most likely be able to restrict USB ports to 2.0 in the BIOS (at least I can do that); have you checked whether your Mac hardware offers something comparable? – Run CMD Oct 12 '15 at 12:48
  • I have searched the web for an similar interface like BIOS for Mac, but haven't found anything useful. – Alin Roman Oct 12 '15 at 12:49
up vote 0 down vote accepted

Ok, I just bought an USB 2.0 hub. Plugged the device in the USB hub, plugged the USB 2.0 hub in the USB 3.0 port on my laptop and it worked. The device is fully recognized and is working properly.

  • Thanks for closing the loop on your question. Are there any details you can add to your answer that might be helpful to others with a similar problem? – fixer1234 Oct 12 '15 at 21:04
  • I guess that means the device was not entirely USB-compliant, so some sort of signaling error lead to the port not switching to USB 2.0. – Daniel B Oct 14 '15 at 7:39

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