disk format - Update OS X recovery USB stick with Mavericks

  • Benoit Duffez

    I've got a Snow Leopard 8GB USB stick that I got from my MacBook Air. Now that Mavericks is available, I'd like to update that USB stick with Mavericks.

    I can't seem to be able to format that disk:

    $ diskutil list
       #:                       TYPE NAME                    SIZE       IDENTIFIER
       0:     Apple_partition_scheme                        *8.1 GB     disk1
       1:        Apple_partition_map                         30.7 KB    disk1s1
       2:         Apple_Driver_ATAPI                         2.0 KB     disk1s2
       3:                  Apple_HFS Mac OS X Install        7.7 GB     disk1s3

    I've tried the Disk Utility, it recognises the USB stick as an optical disk, and it refuses to erase it (I guess because my MacBook Air doesn't have an optical drive).

    I've tried the following:

    $ sudo fdisk -i /dev/disk1
    fdisk: could not open MBR file /usr/standalone/i386/boot0: No such file or directory
    Do you wish to write new MBR and partition table? [n] y
    fdisk: /dev/disk1: Permission denied
    $ sudo dd if=/dev/zero of=/dev/disk1
    dd: /dev/disk1: Permission denied
    $ sudo diskutil eraseDisk jhfs+ newdisk /dev/disk1
    Started erase on disk1
    Unmounting disk
    Error: -69877: Couldn't open device

    What else can I do? I'd like to erase it and format it as HFS+ (journaled).

  • Answers
  • Bert

    The Apple-provided system restore USB stick is read-only. There are a few un-official tools you can use to make it into a 'regular' USB stick if you search. More information here.

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    osx - How to format the OS X installer USB stick that comes with MacBook Air?
  • Jonathan Mayhak

    When you purchase a new MacBook Air they give you a mini-USB drive that is used to reinstall OS X and iLife '11.

    How can I format this USB stick and put whatever I want on it?

    The option to format is not available in Disc Utility and the USB stick mounts as a CD.

    Note: I realize what the disk is used for and what Apple says on their FAQ. My question isn't "What do you think about formatting the USB?" it is "How can I format the USB?" The answer may be that it is impossible.

  • Related Answers
  • Dori

    From Apple's MacBook Air: Frequently Asked Questions about Software Reinstall Drive:

    Note: The MacBook Air Software Reinstall Drive is read only. You cannot erase it, reformat it, or reuse it as a general purpose USB storage device.

    Honestly, thumb drives are dirt cheap these days—why would you want to lose your only way to reinstall your OS?