How to "burn" an ISO to USB flash drive?

Discussion in 'OS X' started by glitch44, Nov 11, 2008.

  1. macrumors 65816

    Feb 28, 2006
    I'm sorry, this is probably a noob question, but I have a linux LiveCD ISO I need to be bootable on a USB flash drive.

    Can I do this with DiskUtil or through the terminal?

    Thanks for any help you can provide...
  2. Administrator emeritus


    Jan 15, 2006
    The Kop
    I believe you can do this through Disk Utility. Select the Thumb drive and then go to the restore tab. Drag the .iso to the source and do the same for the thumb drive in the destination.

    You might need to check the formatting of the drive for the linux distro.
  3. thread starter macrumors 65816

    Feb 28, 2006
    Thanks for the help!
  4. macrumors newbie

    Nov 26, 2008
    Here's what I did:

    1) Created a fat partition
    2) Clicked on restore, dragged the ISO to Source, the partition to Destination
    3) Clicked Restore followed by typing in my password

    What I got was:

    "Restore Failure
    Could not validate source - error 254"

    The ISO is md5sum tested and burning it to a cd works.

    Any ideas?
  5. macrumors 6502


    Sep 25, 2007
    Athens, Greece
    try mounting the .iso and drag its volume in the destination field

    EDIT: bah ignore this, i need some sleep
  6. macrumors newbie

    Oct 10, 2002
    I also want to do this. I tried to use dd, but it doesn't work. dd requires the drive be unmounted, but there is no way to unmount a flash drive. Even on a fresh boot, the umount command returns "Resource busy" and Finder unmounting seems to put it in some zombie state that's no longer accessible to dd.
  7. Moderator emeritus


    Jan 9, 2004
    Grand Rapids, MI, USA

    - Using dd to write the ISO contents directly to the USB absolutely does not work.

    - Using any other method to copy the ISO contents also doesn't work.

    Both are true for any distribution of Linux.

    The core problem is that how an ISO is converted into bootable USB is not the same from one distribution to another.

    The best option is unetbootin:

    Unetbootin is an automated tool that will take many different ISOs (it isn't guaranteed to work if you use it with an ISO that isn't on its approved list, though, so you might want to check the compatibility first) and makes bootable flash drives off them.

    But there is no OS X version of it, AFAIK, so the USB must be created using unetbootin in a Windows or Linux environment.

    If that's not a possibility, you can use OS X, and follow tutorials appropriate to your distribution, such as the ones at, but you'll have to find an alternative way to put a bootable MBR on it and syslinux it. (FWIW, I know I've done this at least once -- it's even possible to make a bootable USB of an Intel Linux distribution purely from a PPC Mac. I had to do this because I inadvertently completely jacked the Ubuntu installation on my Eee to the point that I could not recover, and I didn't happen to have a working bootable flash drive for it at that moment).

    Since Unetbootin came out, I pretty much avoid any other method if at all possible.... :eek:
  8. macrumors newbie

    Jan 28, 2008
    "but you'll have to find an alternative way to put a bootable MBR on it"

    I'm using Mac OS X 10.4.11 on an iBook G4 and in Disk Utility under the Partition tab, if you click options, there is a choice of partitions scheme, you can choose Master Boot Record (MBR) "To use the disk to start up DOS and Windows computers"

    Things are easy on a Mac :)

    To get around the "busy" thing when using dd:
    In Disk Utility: Unmount the volume of the usb drive, not the drive itself.

    I recently used this to put an .img of Ubuntu Netbook Remix on a usb flash drive following

    Only change I had to make was to use "bs=1024" instead of "bs=1M" for the blocksize argument in dd

    And you can get the /dev/disk? number from Disk Utility too, select drive and press apple+i
  9. macrumors newbie

    Nov 25, 2009
    This absolutely DOES work. Do NOT insert the *.dmg or *.iso file into the source box. Instead, INSERT THE VOLUME from the mounted image into the source box in Disk Utility. :cool:
  10. macrumors newbie

    Dec 17, 2009
    I've been reading forums all over to try to create a bootable USB version of slax with my Macbook. I'm running 10.5.8.

    up to this point I have a configured USB with a FAT32 partition and I have both the slax-6.1.2 iso and the raw files extracted from the slax-6.1.2.tar. I have followed the previous advice about "burning" the iso to the USB with the disk utility trying the iso and the mounted volume of the iso. I keep getting the same failure:
    "Restore Failure
    Could not validate source - error 254"
    even with the mounted volume as the source. Am I missing a step?

    also, I'm not very experienced with command line interface, but i've tried running the in the USB but I get an error like this:
    egrep: /proc/mounts: No such file or directory
    egrep: /proc/mounts: No such file or directory
    egrep: /proc/mounts: No such file or directory
    Can't find device to install to.
    Make sure you run this script from a mounted device.
    any advice would be greatly appreciated

  11. macrumors newbie

    Feb 3, 2009

    i'm 99% sure the error 254 indicates an incorrect drive format/partition type. i've noticed that whenever i get that error, if i click "info" for the disk image, it is of a format that i can't apply using disk utility. i.e. it will be like iso 9886 or UDF, while i can only choose HFS+, FAT, etc... there is a program called macFUSE that can deal with extra format types -- and i hate to be another a**hole to post without a solution, but i would try looking into using macFUSE to give OS X the ability to deal with those formats, then maybe you'll be able to partition your media to the appropriate file system to match the source image.

    personally, i boot into windows and use unetbootin to make linux discs. if you don't have windows to boot into, you can download virtualbox for free, and make a virtual linux system from your .iso, then from the virtual system get unetbootin [for linux] and burn your disk.

    huge pain in the a- workaround, but it's all i've got. i feel your pain. i've always had to go to dirty dirty windows to make my linux discs, but mostly for lack of energy to go back to trying to figure out doing it on os x. hell, i'm on the windows side now trying to find similar solutions to the file system crap so i can put my windows, os x, and linux installs all on one firewire drive (i've re-installed all of them 5 or 6 times in the last two days trying to get my system to triple-boot, and installing from disc takes sooo long each time, but that's a whole other story)

    ***EDIT thinking about the virtual machine approach, you can convert the virtual machine to a physical machine and place its contents wherever? i just read about it, so obviously i haven't tinkered with the idea --
  12. macrumors newbie

    Jul 9, 2010
    Its actualy pretty easy to do this in the terminal:

    Lafka:~ lafka$ diskutil list
    and it returns something like
       #:                       TYPE NAME                    SIZE       IDENTIFIER
       0:      GUID_partition_scheme                        *1.0 TB     disk0
       1:                        EFI                         209.7 MB   disk0s1
       2:                  Apple_HFS Macintosh HD            999.9 GB   disk0s2
       #:                       TYPE NAME                    SIZE       IDENTIFIER
       0:     FDisk_partition_scheme                        *4.1 GB     disk1
       1:                 DOS_FAT_32 GENTOO LIVE             4.1 GB     disk1s1
    Now unmount the disk using diskutil replace the disk number with the id of your usb stick

    Lafka:~ lafka$ diskutil unmountDisk /dev/disk1
    And use DD to write again replace the disk number
    dd if={ISO_IMAGE_HERE_} of=/dev/disk1
    Replace if={} with the path to your iso image
  13. macrumors newbie

    Jun 28, 2009
    Ohh my god!!! This one takes lot of time ... i dont know why .... I am writing 4g of ISO for Fedora and so far it took 1 hour and is still going on ....
  14. macrumors newbie

    Jan 28, 2008
    block size

    maybe the block size argument would make it faster.

    Sounds like a similar case here :

    From "man dd" (this made me lol):

    bs=n Set both input and output block size to n bytes, superseding the
    ibs and obs operands. If no conversion values other than
    noerror, notrunc or sync are specified, then each input block is
    copied to the output as a single block without any aggregation
    of short blocks.

    got it :)
  15. macrumors newbie

    Nov 2, 2010
    If you try to restore it through Disk Utility to the thumbdrive, thats going to make the thumb drive an exact copy of the bootable cd. So, why wouldnt you BURN a copy of the iso onto a DVD, then install the OS to a thumbdrive? Much simpler, takes alot less time. Also, fewer headaches.

    Open the .iso in Disk Utility, put a Blank DVD in the drive, click burn. Once done, boot off the cd, and when asked where to install to, find the drive that matches your thumb drive. Simple, and its a full bootable version of the OS. Not the LiveCD...
  16. macrumors newbie

    Jan 28, 2008
    Not everyone has an antique shop or museum close by to find a computer with dvd drive.
  17. macrumors member


    Jun 24, 2009
    Dansville, NY

    Yes just drag the Mounted drive from you desktop into the box in Disk Utility, same thing with the mounted ISO into the other box! Waiting for my USB to finish now then to try and boot iDeneb on my Dell Inspiron 1501!!
  18. macrumors newbie

    Nov 17, 2010
    This method did not work for me. I got the exact same error using this method as with using the .ISO file as source.
  19. macrumors newbie

    Jul 11, 2009
    My Fix for the "Restore Failure" error

    I know this is an old thread but I was getting the same "Restore Failure" error when I tried to use RESTORE in Disk Utility to burn an ISO onto my USB drive.

    So what I did was create an new image in Disk Utility and copied over the files of the mounted ISO into the new Disk Image -Using the new Disk Image I was able to do the Restore onto my USB drive.

    Hope this helps anyone who was having similar problems.:)
  20. macrumors newbie

    May 11, 2011
    at home, sometimes at work
  21. macrumors newbie

    May 11, 2011
    at home, sometimes at work
    Unfortunately, this way it looks like it would not have made it bootable :-(. Trying the Disk Utility now. I was trying to make HP DL server firmware image to boot from USB, as I couldn't find the HP tool to make the USB bootdrive on a Mac.
  22. sootysam, May 18, 2011
    Last edited: May 18, 2011

    macrumors newbie

    May 18, 2011
    How to install from USB Stick rather than CDROM

    Am using a USB Stick to install Ubuntu Server 11 on a Linux machine, rather than using CD-ROM.
    (Am using Mac OSX 10.6.7 to download my iso, configure USB stick, and then copy .iso to it)

    This worked for me
    - Insert 4GB USB Stick
    - Open Disk Utility, Click ERASE. Format USB using MS-DOS (FAT)
    - When Disk appears in Left hand column, right click and get Information (note down the "Disk Identifier : eg disk6")
    - Then right click the Disk and select Unmount. (the drive still shows but the disk unmounts)
    - Switching to the Terminal App
    - Change to superuser / root, by issuing: sudo su - (then enter your password)
    - Change directory to where ever your recently downloaded .iso image is stored, eg: Downloads
    - My file iso is called ubuntu-11.04-server-amd64.iso, (approx 650mb) so use the following command:
    dd if=ubuntu-11.04-server-amd64.iso of=/dev/disk6 bs=8192
    - This will start copying the file to the USB stick.
    - There is no "verbose" or screen "output" of what is happening. But after 15mins you should see something like:

    The end result is a USB stick containing the installation media of Ubuntu Server (swap Ubuntu server for your media download of choice). Happy Days.
  23. macrumors newbie

    Jun 2, 2011
    Looks like resetting this NVRAM stuff is something to pursue.
    What could be the negative effects from trying this ?
    I am pretty sure that bootable iso is reliably on my USB card,

    /gunnar iMac G4 20" LCD with USB 2.0 / Leopard
  24. macrumors newbie

    Jun 22, 2011
    You can use Disk Utility to make the drive bootable, you do it by creating a new partition on the USB drive and selecting Master Boot Record from the Options button, then you can use unetbootin to copy over the contents of the iso you want ... I hope. I'm in the middle of doing this presently.

    Make sure you format the partition as MS-DOS also.
  25. Candlejack, Jun 22, 2011
    Last edited: Jun 22, 2011

    macrumors newbie

    Jun 22, 2011
    Final Solution

    Well, I was dealing with this problem, but after a little digging I found a be-all end-all solution for creating Windows/Linux bootable Flash Drives on the mac.

    Disk Utility, for whatever reason, is prohibited from writing Joliet (ISO 9660) onto MS-DOS FAT 32 Flash Drives, though it should definitely work.

    The best way to accomplish your goal is the following:

    Open Terminal

    Type 'diskutil list'. You'll see your primary hard drive (probably listed under /dev/disk0) and your Flash Drive, which will be listed as /dev/disk#, with # being any number that isn't zero. REMEMBER THE DISK LOCATION

    In the next line, type 'diskutil unmountDisk /dev/disk#'. You'll see this message on success:
    Unmount of all volumes on disk# was successful

    Now type, 'dd if=(DRAG ISO/DMG HERE) of=/dev/disk# bs=1m'

    Do not forget bs=1m! The blocksize cannot be any different from this because of the nature of the MS-DOS FAT partition structure. Using smaller block sizes can potentially corrupt the newly created iso and will slow down the process tremendously.

    Now give your computer some time (anywhere from 15 minutes to 2+ hours depending on file size) to finish this procedure.

    If you're unsure about the dd command and how it functions, head over to

    An awesome program I saw makes use of the dd command and includes a progress bar! Very cool stuff!

    With this program, you don't have the option to change the blocksize, but the addition of a progress bar makes it worth it.

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