Not able to echo to slots in BeagleBone Black
<p>I newly started working with BeagleBone Black and Device Tree Overlays.
I wrote a Device Tree Overlay, compiled it and <em>copied to /lib/firmware</em>, but when I am trying to echo it to <em>/sys/devices/platform/bone_capemgr/slots</em> I get this error:</p>

<pre><code>root@arm:~# echo APOLLO-PCB-RevA &gt; /sys/devices/platform/bone_capemgr/slots
bash: echo: write error: Invalid argument
</code></pre>

<p>When I <em>cat</em> the slots I find the following:</p>

<pre><code>root@arm:~# cat /sys/devices/platform/bone_capemgr/slots
 0: PF----  -1 
 1: PF----  -1 
 2: PF----  -1 
 3: PF----  -1 
</code></pre>

<p>Can anyone please tell me what is the issue?</p>