I have an old MacBookPro3,1 to which I've added an ExpressCard/34 USB 3.0 adapter. The card is recognised by OS X out of the box, but when I connect a device to it I can't talk to it unless I wait forever. It's like the transfer rate is snail slow rather than not being able to communicate.

I'm running OS X 10.11.4 (15E65). The card is described like this:

  Type: USB eXtensible Host Controller
  Driver Installed: Yes
  MSI:  Yes
  Bus:  PCI
  Vendor ID:    0x1912
  Device ID:    0x0015
  Subsystem Vendor ID:  0xffff
  Subsystem ID: 0xffff
  Revision ID:  0x0002
  Link Width:   x1
  Link Speed:   2.5 GT/s

This card works fine on my Linux laptop. It also works fine on the Mac when booted into Ubuntu. It feels like I shouldn't need any 3rd party .kext on OS X.

What else can I try to get this to work?

  • Who is the manufacturer of your ExpressCard?
    – Allan
    Apr 2, 2016 at 13:42
  • Objectively - what transfer rate is "snail slow"? How are you measuring transfer time?
    – bmike
    Apr 2, 2016 at 13:46
  • Objectively: a 32K block takes ages to transfer. I used dd if=/dev/rdisk2 of=/dev/null bs=32768 count=1 as a last test. Before that, I noticed that my drive did show up in /Volumes after a while, and doing a touch test.file on it would take ages. Unmounting would timeout. It never got shown in Finder, but TimeMachine did see it and attempted to back up to it (I used this drive on USB 2.0 before, and it knows about it)
    – Radu C
    Apr 2, 2016 at 14:23
  • 1
    The manufacturer is probably an "independent" in China. There's no brand on it. It just boasts a "NEC UPD720202 Chip". Linux agrees with that identification.
    – Radu C
    Apr 2, 2016 at 14:24

1 Answer 1


I also have that Macbook Pro (15-inch, 2017, 2.2Ghz) and a non branded USB 3.0 ExpressCard with the NEC UPD720202 Chip. I had been able to install it in my Mac some time ago following instructions found on web, but it stopped working as soon as I upgraded to El Capitan. Now I decided to give it another shot, as some time has passed by. So I found some potentially useful information in some in "hackintosh" related websites and I believe I was able to get it to work again by following the instructions on this site:


Basically, it implies that we give up on some important Apple's security measures by enabling the "kext-dev-mode", typing this command in the Terminal:

sudo nvram boot-args="kext-dev-mode=1″

You may also need to get an updated kext file. That page is providing the download link for one that should be compatible with El Capitan, and maybe you can find some other option in tonymacx86.com.

You also need to disable System Integrity Protection. The instructions are here:


It consists in entering Recovery Mode (CMD+R right after turning on your Mac) and typing this in the Terminal:

csrutil disable; reboot

Obviously, I would advise you to first start by making a full backup of your files and also by reading those articles and try to understand the security/privacy implications of each step and consider you you are willing to take the eventual risk. I would try to get those two security measures back in place and see if the ExpressCard keeps working as expected. That's what I intend to do in my next reboot, when I get my current backup done. ;)

Update: I have just re-enabled System Integrity Protection by using the shell command csrutil disable; reboot in Recovery Mode. It seems to be working just fine.

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