For some reason (at least as of this writing), the official Ubuntu documentation on creating a bootable USB of Ubuntu for Macs is now recommending using UNetbootin. I haven’t found that to actually work. I dug up a cached copy of the old instructions (which do work), but I wanted to document the old procedure here, just in case the cached copy later becomes inaccessible.

Here are the steps to get a bootable-to-Mac USB of Ubuntu

Go to the list of alternative downloads and use a BitTorrent client (e.g., Transmission) to download a .torrent of the desktop version of Ubuntu.

Launch up /Applications/Utilities/Terminal.app.

In the terminal put in

but substitute in your actual paths to the names of the files.

You may notice that your target.img ends up turning into target.img.dmg, which is totally fine.

Run

to get a list of the drives/partitions on your Mac.

Plug the USB stick in and run

again to find the new drive name, based on what didn’t show up the last time you ran the command. For the sake of this example, we’ll assume it’s /dev/disk2, but pay careful attention to your actual USB’s name, which may be different.

Unmount the USB (without unplugging it physically) by running this command

(being sure to substitute in your actual disk number for disk2).

Copy the .img (or .img.dmg) file to your USB using dd:

Put in your actual disk number, if it’s not 2.

If it copied correctly, you should actually get an error message: Click Eject.

Then remove the USB drive from your Mac and put it in the Mac you want to boot from. Hold down the option key while booting up, and then select EFI as the drive to boot from.