FAQ - Frequently Asked Questions - Knowledge Base

[SK-3500 Super-S] Unable to boot Mac OS from external drive when connected via FireWire

Under some circumstances, booting the system (Mac OS) from the external hard drive does not work when connected via FireWire. This happens when two criterias are met:

  1. The firmware on the SK-3500 Super-S Combo is a fairly recent revision, where the support for large drives over 2.2TB is enabled.
  2. The computer is an older hardware, where the motherboard does not support large drives over 2.2TB. Computers that are affected are either PPC based or Intel based machines up to 2006 (e.g. MacPro 1.1). Machines from 2007 (e.g. MacPro 2.1) and later are not affected.

To solve this issue if using a newer computer is not an option, you can disable the 2.2TB support of the hard drive enclosure. However, doing so means that large drives over 2TB are no longer supported.


  • The firmware has to be updated when the device is connected via USB.
  • The firmware can not be updated if there are no drives installed.
  • After the firmware update, drives larger than 2TB are no longer supported.
  • If the firmware update fails, please make sure to update the firmware to the latest version as seen on our website first and then try it again.


  • Never turn off your unit during the firmware update procedure. This may damage your device! If the upgrade fails (e.g. power supply failure during firmware update), you may not be able to operate your device anymore.
  • This firmware is only for the newer PD-SATA Super-S Combo with the OXUF934DSB chip and not the older model with the OXUF924DS chip.

This utility is not compatible with the SK-3500 Super-S3 (USB 3.0) only with the SK-3500 Super-S (USB 2.0).

How to update the firmware

  1. Download the firmware utility and save it on your local disk. [Mac Utility] [Windows Utility]
  2. Turn on your external drive and connect it to your computer via USB.
  3. For Mac users, open the *.dmg file to mount the folder and then double-click on Setup to start the updater utility.
    For PC users, double-click on the *.exe file to start the updater utility (Windows 7 users need to right-click and run it as administrator).
  4. Wait until the device has been recognized by the updater utility.
  5. Click Upgrade to start the firmware update.
  6. Wait for the update process to complete and make sure never to turn off the power during the firmware update procedure!
  7. When the upgrade is completed, click Exit to close the program. After the firmware update, the system will restart by itself to load the new firmware, so the device will be disconnected and mounted again.
  8. Done!