title: building android: system.img is missing
body: <p>On Mac OS X, after the following steps:</p>
  
  <ol>
  <li><code>$ lunch</code>, and pick <code>full-grouper-userdebug</code></li>
  <li><code>make -j8</code></li>
  <li><code>adb reboot bootloader</code></li>
  <li><code>fastboot flashall -w</code></li>
  </ol>
  
  <p>I got the error:</p>
  
  <p><code>error: could not load system.img: No such file or directory</code></p>
  
  <p>Any idea?</p>