How to make Ubuntu ISO bootable on a USB stick with OSX?

I have a Macbookpro and I'm planning to create a multiple boot. I've already created the necessary partitions and downloaded image file (i386)

When I try to create a bootable USB stick from the ISO file, by means of "recovering" the disk image into the USB drive using Disk Image Utility, I get the following message:

Could not validate source - corrupt image

The disk image can't be mounted in OSX either, I also get a similar message.

Is there any way to make a bootable Ubuntu USB stick from an ISO image in OSX?

Thanks

The problem you're having is that is file you downloaded is corrupted, hence, not useful.

To solve this, download Ubuntu again. Once done, try again. You can follow the Official Guide for OSX:

1: Download Ubuntu

2: Convert the ISO file

Convert the .iso file to .img using the convert option of hdiutil

hdiutil convert -format UDRW -o ~/path/to/target.img ~/path/to/ubuntu.iso

Note: OS X tends to put the .img ending on the output file automatically.

3: Determine the media to install

Run diskutil list to get the current devices. Insert your USB and the run again diskutil list. The new device its your USB.

4: Install into the USB

Unmount your device (not physically) with diskutil unmountDisk /dev/diskN where N is your USB number and execute

sudo dd if=/path/to/downloaded.img of=/dev/rdiskN bs=1m

Notes:

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

5: Eject

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

6: Boot

Restart your Mac and press alt/option key while the Mac is restarting to choose the USB stick.

Step 4 needs to change:

unmountDisk /dev/diskN

should now be:

diskutil unmountDisk /dev/diskN

For reference, see http://hintsforums.macworld.com/showthread.php?t=107929, as this is what worked for me where as the instructions above did not. Using OSX v. 10.8.2