title: What filesystem or file format is this?
body: <p>I have a great amplifier that sadly no longer gets any support (a Kickstarter gone bad). It can however be upgraded with an .img file. The unit runs Linux and the OS is installed on some kind of embedded storage (not a disk drive)</p>
  
  <p>I have tried writing the img to an SD card with no success. A lot of Kickstarter backers will be very happy if we can figure this one out.</p>
  
  <p><a href="https://i.stack.imgur.com/xJHji.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/xJHji.png" alt="enter image description here"></a></p>
  
  <p><a href="https://i.stack.imgur.com/np06d.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/np06d.png" alt="enter image description here"></a></p>
  
  <p>Thanks</p>
  
  <p>Update: </p>
  
  <pre><code>$ file usbupgrade_O.0.31.69.img 
  usbupgrade_O.0.31.69.img: data
  </code></pre>