Creating a bootable USB stick with Mac OS X in 10 easy steps


Logged in as administrator
Because you are going to use the sudo command, you have to be logged in as an administrator. A non-administrative account will not work.
Formatted as FAT32
Start the application Disk Utility (located in the folder /Applications/Utilities/ of your Macintosh HD volume), stick in your USB stick, and format it as FAT32. If you don’t know how to do that, read this instruction on the AppleInsider forum, or do a Google search on FAT32 disk utility.

The Ten Steps

Here are the steps in words:

  1. Download the .iso file. This also can be an .img file. Let’s call it moblin.img.
  2. Rename the .iso file to .dmg. In our case, rename moblin.img tomoblin.dmg.
  3. Right-click on the .dmg file and select Get Info. Write down the full path name as mentioned in the dialog box. We will need that for step 9.
  4. Start a Terminal window. The Terminal application is located in the folder /Applications/Utilities/ of your Macintosh HD volume.
  5. In the Terminal window, type:
    diskutil list
    and press the Enter key. Now a list of your storage devices is displayed in the Terminal window, underneath what you typed earlier.
  6. Put the USB stick in the USB port of your Mac.
  7. In the Terminal window, type again:
    diskutil list
    and press the Enter key. Now you see the same list, but with an extra storage device. The location of that device has the format /dev/diskN, where N is a number. In my case it was /dev/disk4. Write that down.
  8. In Terminal, type
    diskutil unmountDisk /dev/diskN
    and press the Enter key. Use the N from step 7. This will unmount the USB stick (it will disappear from your desktop).
  9. In Terminal, type
    sudo dd if=/path/to/file.dmg of=/dev/diskN bs=1m
    and press the Enter key, where /path/to/file.dmg is the full path from step 3, and /dev/diskN from step 7. You will be asked to enter a password. This is why you must be logged in as an administrator, a non-administrator does not have to privileges to perform this operation. This operation takes quite a while (10 minutes in my case). Be patient and let it do its thing.
  10. In Terminal, type
    diskutil eject /dev/diskN
    and press the Enter key. Again N is the number we established in step 7.

Now you can take out your USB stick and use it to boot your netbook. Booting your netbook from a USB stick is a whole other matter, which I won’t discuss here.

That is all.


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