Making bootable USB from MAC osx without any apps

  1. Convert the .iso file to .img using the convert option of hdiutil e.g.,

    hdiutil convert -format UDRW -o ~/path/to/target.img ~/path/to/ubuntu.iso
    

    Note: OS X tends to put the .dmg ending on the output file automatically.

  2. Z

    Run

    diskutil list
    

    to get the current list of devices.

     

  3. Z

    Insert your flash media.

  4. Z

    Run

    diskutil list
    

    again and determine the device node assigned to your flash media (e.g. /dev/disk2).

     

  5. Z

    Run

    diskutil unmountDisk /dev/diskN
    

    (replace N with the disk number from the last command; in the previous example, N would be 2).

     

  6. Z

    Execute

    sudo dd if=/path/to/downloaded.img of=/dev/rdiskN bs=1m
    

    (replace /path/to/downloaded.img with the path where the image file is located; for example, ./ubuntu.img or ./ubuntu.dmg).

    • Using /dev/rdisk instead of /dev/disk may be faster
    • If you see the error dd: Invalid number ‘1m’, you are using GNU dd. Use the same command but replace bs=1m with bs=1M
    • If you see the error dd: /dev/diskN: Resource busy, make sure the disk is not in use. Start the ‘Disk Utility.app’ and unmount (don’t eject) the drive
  7. ZNOTE : If you get the error in the end that DIsk is unable to read by this computer .Dont do any thing , just run the command below and physically remove USB.. after that simply click the Ignore of this error.
  8. Run

    diskutil eject /dev/diskN
    

    and remove your flash media when the command completes.