Here’s how to use the dd utility to write a disk image to media under Mac OS X. I tested this with 10.5.2 with both a USB to CompactFlash adaptor, and a USB Imation USB SuperDisk.

  1. Plug the media into your Mac.
  2. If you get a message saying that the media cannot be read, click Ignore.
  3. Open Disk Utility (Applications -> Utilities -> Disk Utility).
  4. On the left-hand column, find that disk that you plan to write to. Select any partitions on that disk that are mounted, and click the Unmount button (not the Eject button). Once unmounted, the partitions should grey out.
  5. On the left-hand column, find that disk that you plan to write to, click it, then click on the Info button.
  6. In the window that pops up, note the Disk Identifier. It should be something like disk2 or disk3.
  7. Open up Terminal (Applications -> Utilities -> Terminal).
  8. Type in the following command, replacing diskx with the Disk Identifier found earlier, and image.img with the name of the image file that you wish to read from.

sudo dd if=image.img of=/dev/diskx