Is it legal to replace something&#39;s firmware?
<p>I'm a software/hardware hacker and I am wondering about how legal it is to replace the firmware of something. This something can be </p>

<ul>
<li><p>a car</p></li>
<li><p>a chinese quadcopter</p></li>
<li><p>a phone</p></li>
<li><p>a Canon EOS 5D</p></li>
<li><p>a (connected) digital thermometer</p></li>
<li><p>a presence sensor</p></li>
<li><p>… anything.</p></li>
</ul>

<p>I know that <em>modify</em> the firmware may be illegal (because of licensing/copying copyrights, usually).</p>

<p>But what if you can't even read the firmware, only replace it with one your wrote yourself?</p>

<h2>It's yours - do what you like with it</h2>

<p>Assuming that you are the legal owner of the device then you are entitled to do whatever you like with it: smash it with a sledgehammer, brush your teeth with it, upload firmware, etc.</p>

<p><strong>Unless</strong>, what you would like to do is otherwise illegal ...</p>

<h2>Copyright</h2>

<p>It is unlikely that in buying the item you also bought the copyright in the firmware. More likely you have a licence to use it and that permission is limited to what the licence allows.</p>

<p>So, <em>if</em> you can write the firmware without using their firmware as a starting point then you can upload your new firmware. Personally, I think it would be next to impossible to build working firmware without knowing what their firmware does but if you can do so: well done.</p>

<h2>Regulatory</h2>

<p>Some of the things you name require government regulated designs - cars and telephones spring to mind. Your firmware is not part of that government approval so, for example, you couldn't drive a modified car on a public road, or connect a modified telephone to a telecommunications carrier without getting those approvals.</p>

software hacking hardware