For the Mac instructions (page 4, at the bottom), you may want to switch<p><pre><code>    diskutil unmount &#x2F;dev&#x2F;diskNs1
</code></pre>
to<p><pre><code>    diskutil unmountDisk &#x2F;dev&#x2F;diskN
</code></pre>
The former does not work if the disk has multiple partitions.<p>Also you may want to put that command before the dd, because most people will have to run it.