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I was following the instructions on this website to create a bootable USB flash drive on a Mac:

The instruction: hdiutil convert -format UDRW -o ~/path/to/target.img ~/path/to/ubuntu.iso does not create a valid file that the disk utility can copy to the USB drive, making installation on a USB drive useless.

I've been repeating these instructions for days with no luck. The only thing that does not work is the .ISO to .IMG conversion. Is there a way to download Ubuntu 12.04 LTS 64-but Desktop in a .IMG file already?

Unfortunately, my install notebook does not have an optical drive so USB is the only way.

Thanks for your help!

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I would burn the ISO on a cd/dvd, boot using the cd/dvd, and then use Ubuntu live to create a bootable usb stick. :) – medigeek Jun 12 '12 at 16:25
There is no optical drive. – Rob Jun 12 '12 at 21:08
Which iso are you using? amd64+mac or amd64? Try using ubuntu-12.04-desktop-amd64+mac.iso, not the regular amd64 -- Explanation: and – medigeek Jun 13 '12 at 7:11


hdiutil convert /path/imagefile.iso -format UDRW -o /path/convertedimage.dmg
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ah, I was about to suggest the same :) I also found a wiki article:… – medigeek Jun 12 '12 at 21:02
I tried this and I know this is SUPPOSED to work, but this is where the failure occurs. The DMG file is not created correctly. The MD5 sum of the ISO checks out okay though. I can't figure out why this part of it fails every time. – Rob Jun 12 '12 at 21:09

I can't do this either, the dummy .img.dmg file dissapears when the conversion is over. I have a G5 iMac running OS X 10.4.11

I noticed that it works just fine with smaller .iso files. Could it be that the .iso file we're trying is somehow corrupt?

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