title: How does the raspbery pi know which device tree blob (dtb) to load?
body: <p>A raspberry pi card images includes several different dtb files in the boot partition. For example:</p>
  
  <pre><code>bcm2708-rpi-0-w.dtb
  bcm2708-rpi-b.dtb
  bcm2708-rpi-b-plus.dtb
  bcm2708-rpi-cm.dtb
  bcm2709-rpi-2-b.dtb
  bcm2710-rpi-3-b.dtb
  bcm2710-rpi-3-b-plus.dtb
  bcm2710-rpi-cm3.dtb
  </code></pre>
  
  <p>When the pi boots, how does it know when dtb to select? </p>