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I have 2 machines - a MacBook Pro and a desktop running Fedora, I have a USB drive and a OSX 10.8 dmg. The MacBook won't boot into OSX unfortunately, I'm trying to make a bootable mac usb to recover it.

Any insight? I've tried dmg2img but no success putting that image onto the usb drive.

Is there an easy way to do this?

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up vote 9 down vote accepted

Have you tried "Acetoneiso"?

It'll convert the DMG to an ISO for you. After that, the easiest way I know of to make a bootable USB is using DD.

dd if=/path/to/osx.iso of=/dev/sdX && sync

Note: sdX is an example, you will have to check your flash drive address (usually sdb if you have only one hard disk). Do not add a partition # after that (such as sdb1). This method is a little hard on flash drives (I have killed one or two doing this relatively frequently, but once should be fine).

If you are unfamiliar, DD is a bit by bit copy and sync just verifies that all files have been written to the usb.

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why you cannot directly do DD from the .dmg to the USB ? – Francesco Jan 6 '14 at 20:11
@Francesco - Do some research on the format differences between a dmg (non-standard) and iso (standard) – nerdwaller Jan 6 '14 at 20:19
Accordign to this guide:… this should work on Mac Osx: sudo dd if="location of Niresh disk image" of=/dev/r"identifier" bs=1m So why should not on linux ? – Francesco Jan 7 '14 at 9:22
I just want to add detail to the answer ... why you should to convert the image if it is not required ? – Francesco Jan 7 '14 at 17:24
@Francesco - Again, look at the differences between dmg and iso. iso is a standard, dmg is often contains compressed items, where isos do not. To avoid the few rare cases in which a dmg behaves as an iso, it's best to just convert it to a known valid format. If you write the common dmgs (that contain compression) to a USB, many things do not handle them correctly. So you aren't adding details, you're asking questions without researching it beyond a single case in which your point is true while ignoring the numerous cases in which it is false. – nerdwaller Jan 7 '14 at 17:39

Install dmg2img

sudo apt-get install dmg2img

Convert DMG image file to ISO file

dmg2img -v -i /path/to/image_file.dmg -o /path/to/image_file.iso

Copy ISO image to USB

sudo dd if=/path/to/image_file.iso of=/dev/sdb && sync

sdb is an example. In your case it might be different


You can do the conversion and actual writing in one pass, if you don't need the .iso afterwards: it will take half the time as converting to .iso and THEN writing to the USB device. Just do:

sudo dmg2img -v -i /path/to/image_file.dmg -o /dev/sdb

Again, sdb is an example. In your case it might be different.

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How USB should be formatted? Partitionmap GUID/MBR? Formatting FAT/NTFS/HFS+? – Enthusiast Apr 21 at 13:20

If you can find another Mac, try the Disk Utility App.

You can "Restore" your 10.8 DMG to your USB drive. This will make your USB drive be bootable.

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