title: How to mount the android img file under linux?
body: <p>Recently, I'm interest in the android rom, I want to change and rebuild them.<br>
  So, I did some test on my XOOM, it's very easy to flash something into the machine.<br>
  I got some ROM from MOTOROLA (<a href="http://developer.motorola.com/products/software/">http://developer.motorola.com/products/software/</a>),
  they are some img file, and I want to know what's inside, I hope to unpack them.</p>
  
  <p>I tried the <strong>unyaffs</strong>, it said <code>broken img file</code>.<br>
  I try to mount them, it works great on the system.img, and I can get the file inside.</p>
  
  <p>When I want to mount userdata.img by <code>mount -o loop userdata.img /mnt/userdata</code> (the same as <code>system.img</code>), it tells me <code>mount: you must specify the filesystem type</code> so I try the <code>mount -t ext2 -o loop userdata.img /mnt/userdata</code>, it said <code>mount: wrong fs type, bad option, bad superblock on...</code></p>
  
  <p>So, how to get the file from the inside of <code>userdata.img</code>?</p>