Using USB PCI Cards in Mac OS 9.1/9.2

These instructions are intended for machines that have had a PCI USB card installed after Mac OS installation has occurred, or one running 9.2 without built-in USB ports. The extensions that come with 9.2 have a bug, causing them to not work on Macs without built-in USB. The card and devices plugged into it will appear in System Profiler but will not function, and do not disappear until the machine is restarted.

Picture 1

In 9.1 you could also run the installer again, select Add/Remove, and add in USB Adapter Card Support. This is located in Mac OS 9.1>Network & Connectivity when doing a customized installation.


You will need

  • A Macintosh with a working Mac OS 9.1 or 9.2 installation (See note 1 for prior versions)
  • One PCI USB Card that’s OHCI compliant, installed in the Mac. The vast majority of PCI USB 1.1/2.0 cards support OHCI.
    • Theoretically any OHCI-compliant card will work, but certain configurations are problematic (See note 2)
    • Note that a USB2.0 card will not work at 2.0 speeds as OS8/9 do not support EHCI
  • Mac OS 9.1, either a retail CDROM or the 9.1 update
  • TomeViewer


  1. Insert your OS 9.1 disc or extract the 9.1 update and open the “Installation Tome” filePicture 2
    1. This is located in Software Installers/System Software/Mac OS 9.1
  2. Extract these files from the tome, placing them on your desktop.Picture 3
    1. HID Library
    2. Serial ShimLib
    3. USB Device Extension
    4. USB Mass Storage Support
    5. USB Software Locator
    6. USB Support
  3. Skip to step 4 unless you’re running 9.2. You’ll need to remove the preinstalled versions of these files from your Extensions folder (in your System Folder.) Create a folder on your desktop and place them inside.
  4. Drag the files you extracted onto the System Folder. You should receive a dialog box asking you to confirm placing them in the Extensions folder, click OK. Alternatively you can place the files directly in the Extensions folder.
  5. Reboot. USB should now be working. You may trash the extensions you removed (if on 9.2)Picture 7


  1. Apple provided USB Adapter Card Support 1.4.1 as a separate installer for 8.6-9.0. You may still be able to use the versions extracted from 9.1, however.
  2. All OHCI cards are supposed to work.
    1. I’ve had the best luck with NEC, Lucent, and OPTi-based cards. I’d stay away from VIA
    2. I could not get any USB 2.0 cards to function in a PowerMac 6500. I suspect this might have something to do with PCI 2.2, but I’m not sure. Please comment with your results.