Make a USB stick act like a bootable CD on macOS

1 minute read

This is how I use a usb stick (aka flash-drive) to behave like a bootable CD. This is not the way to create a bootable usb stick, for installing a live OS. That is a different procedure altogether. This is an easy method to make a stick to install Linux on a PC, but I also include the process to convert the .iso to a .dmg for installation on a Mac. I’m using macOS to create the stick, but the steps to do this on a Linux box are similar.

  1. Download the iso file you wish to use.

    Note: The following command is only used if you are going to use the usb stick to install an OS on a Mac. macOS uses .dmg files and this step converts the .iso to a .dmg file. Then simply substitute the converted .dmg in step 6.
     hdiutil convert /path/to/downloaded.iso -format UDRW -o /path/to/converted.dmg2  
  2. Run:

     diskutil list  

    Note which devices are present.

  3. Insert usb drive.

  4. Again, run

     diskutil list  

    This time note the additional device. Example:(/dev/disk2)

  5. Unmount the usb drive using the device name from step 4.

     diskutil unmountDisk /dev/disk2
  6. Run*

     sudo dd if=/path/to/downloaded.iso of=/dev/disk2 bs=1m  

    *WARNING: Make sure you are writing to the correct device before hitting return! dd is powerful, especially with sudo and will blow away data without warning. Really!

  7. Finally, eject the usb stick.

     diskutil eject /dev/disk2

That’s it!