Making a bootable USB?

Discussion in 'iMac' started by GelleCC, Apr 8, 2012.

  1. GelleCC macrumors regular

    GelleCC

    Joined:
    Jul 13, 2008
    Location:
    Seattle, WA
    #1
    I have done a lot of looking on Google, but I keep getting varied answers on how to make a bootable USB with an OS on it..

    Before you start, I am a student at a University and I AM ALLOWED TO LEGALLY DOWNLOAD both Windows7 and Snow Leopard/Lion.

    That being said, I have downloaded SL and windows 7 (my iMac is still at Leopard). I will end up wanting to have windows and osx on my iMac.

    I am trying to make a bootable flash drive (windows was downloaded as a .img and OSX was a .dmg).

    I found this guide on how to make a bootable USB drive using a Mac for Linux:
    "We would encourage Mac users to download Ubuntu Desktop Edition by burning a CD for the time being. But if you would prefer to use a USB, please follow the instructions below.

    Note: this procedure requires an .img file that you will be required to create from the .iso file you download.

    TIP: Drag and Drop a file from Finder to Terminal to 'paste' the full path without typing and risking type errors.

    Download the desired file
    Open the Terminal (in /Applications/Utilities/ or query Terminal in Spotlight)

    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.

    Run diskutil list to get the current list of devices

    Insert your flash media

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

    Run diskutil unmountDisk /dev/diskN (replace N with the disk number from the last command; in the previous example, N would be 2)

    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.

    Run diskutil eject /dev/diskN and remove your flash media when the command completes

    Restart your Mac and press alt while the Mac is restarting to choose the USB-Stick"

    Like I said, this is for a downloaded ubuntu.img, but would the same code work for a .dmg? So I can make a bootable USB drive of OSX/Windows for my mac? I can't burn DVD's because my superdrive is broken.

    Thanks in advance!
     
  2. simsaladimbamba

    Joined:
    Nov 28, 2010
    Location:
    located
    #2
    It is actually quite simple, even with a pirated version of Mac OS X, unless you can't boot into Mac OS X.
    If you can, mount the DMG file in Finder, open CarbonCopyCloner, select the mounted Mac OS X 10.6 Snow Leopard Installation DVD image as SOURCE and the properly formatted* USB flash memory thumb drive or external HDD as TARGET and press CLONE.
    Then you can boot from it.

    *
    And if that does not work, get any external optical disk drive (ODD) connectable via USB and the 29 USD Upgrade DVD for Mac OS X 10.6 Snow Leopard.
     
  3. GelleCC, Apr 8, 2012
    Last edited: Apr 8, 2012

    GelleCC thread starter macrumors regular

    GelleCC

    Joined:
    Jul 13, 2008
    Location:
    Seattle, WA
    #3
    LOL, I am completely serious, however, I do have legitimate, legal copies that I was able to download from my university (probably the least they could do since tuition is always rising).

    I decided to try out your way but it doesn't seem to work. I plugged it into my iMac restarted and held "alt/option". The iMac went to the "choose a drive" menu, but the only available drive was the HDD.

    CarbonCopy finished the job with OSX "Task finished at: Sun Apr 8 16:52:38 PDT 2012
    Time elapsed: 00:02:08
    Data copied: 944.09 MB"

    but still didn't load.

    I do have a question. I have a properly formatted 16Gb flash drive with 2 partitions (8GB each since both OSX and the windows7 require 8GB ... Is what seems to be consistent across all the "make a bootable USB drive" guides I've read. Will I be able to do the same thing with the Windows 7 .img? (can you mount .img the same way you would a .dmg?).

    So I will try it to see if it works!

    Thanks!
     
  4. GelleCC thread starter macrumors regular

    GelleCC

    Joined:
    Jul 13, 2008
    Location:
    Seattle, WA
    #5
  5. simsaladimbamba

    Joined:
    Nov 28, 2010
    Location:
    located
    #6
    944 MB is too small for the Mac OS X installation DVD.
    The copy I made from my Mac OS X 10.6 Snow Leopard DVD (10.6.3) is 7.27 GB in size, is your .CDR (or .DMG) in that vicinity?

    Did you format the USB flash memory thumb drive correctly, including the partition map scheme?
     
  6. GelleCC thread starter macrumors regular

    GelleCC

    Joined:
    Jul 13, 2008
    Location:
    Seattle, WA
    #7
    Ahh I figured it out.

    The way my school makes you download software is really weird. You have to download software to download from the school, and then you can download the program. I did something funky and it wasn't working right (laptop went to sleep? Idk). But I went and got it again and now it seems to be working.

    Still haven't tried the Win7.img
     
  7. simsaladimbamba

    Joined:
    Nov 28, 2010
    Location:
    located
    #8
    For that: http://www.youtube.com/watch?v=mwX9cmJ8BoM , it worked for me when using an external USB HDD as source for a Windows 7 install on a friends PC with a broken ODD.
     
  8. wemarsh macrumors newbie

    Joined:
    Dec 15, 2012
    Location:
    Chalon-sur-Saône, France
    #9
    I know this is pretty dead, but I wanted the solution to be available to future Googlers. I've done a bit of research on this issue lately, and to the best of my knowledge it is impossible to USB boot from anything other than an OSX image on a Mac. Please correct me if there is a way.
     
  9. GelleCC thread starter macrumors regular

    GelleCC

    Joined:
    Jul 13, 2008
    Location:
    Seattle, WA
    #10
    As far as I know, you are (almost) right.

    As I understand it, the file system/storage is different (obviously) from Mac to pc. That's why an osx bootable doesn't work on a pc (unless its a hackintosh) or making a windows iso USB. However, using terminal on osx, you can make a bootable img of Linux that WILL work cross platform. I'm assuming that's because of Linux being, well, cross platform.

    I ended up trying to make a windows 7 bootable usb on a Linux computer using the terminal (the commands are essentially identical). Then I tried a couple different applications on Linux (can't remember them but none of them worked). Then unetbootin and carbon copy cloner on Mac. Then just jumped over to a pc and used winusbmaker and it worked just fine.
     

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