Google’s Chromecast is the epitome of a software-first device. Nearly all of its capabilities are defined by software, and usually not even software that’s on the Chromecast itself. 

But the Chromecast, for all its hands-off simplicity, does have a single hardware button: an emergency reset button on the back. It’s a testament to the importance and reliability of physical inputs over software solutions. 

Odds are, most people will never use the Chromecast’s reset button. Whether you have the original Chromecast, a second-generation model, or a 4K Chromecast Ultra, this button only has a single function: if all else fails, you can hold it down to factory-reset the hardware back to “fresh-from-the-box” settings. 

(The process is actually an interesting one: pressing the button forces the Chromecast to boot up into a USB boot mode, where it looks for a local copy of a signed system image and loads it. Enterprising users have tried to use this mechanism to load their own software on Chromecasts, too!)

It’s not a button press that can be taken lightly: Google cautions in bold lettering on its support page that “This action will clear your data and can’t be undone.” It’s only the sort of thing that you’d use if you’re selling your hardware or are running into issues so profound that the only solution is a clean slate. Even activating it requires more attention than a simple restart, asking users to hold down the tiny oval button on the back long enough to ensure that you really want to do this. 

But it’s not the mechanism of the button itself or the physical hardware (it’s not a particularly exciting button) that’s fascinating about the Chromecast reset button. It’s that it’s even a button at all. 

Google’s Chromecast is one of the simplest plug-and-play devices around. You take it out of the box, connect it to power and an HDMI port, and you’re good to go. There’s no remote or even a power button. You just plug it in, and it works without any intervention from the user. You then need another device to control everything about the Chromecast, from setup to what you want to stream.

That’s except for this one function: because even such a simple a device that’s reliant so much on software is subject to the vagaries of software. Perhaps you can’t get your Chromecast to connect to your Wi-Fi or your phone refuses to recognize the connection. Hardware is the last resort. Unless the physical button breaks or the entire device won’t boot at all, it’s a way to reset back to normal that can’t be compromised by software issues.

And it’s why even on a digitally focused device like a Chromecast, there’s still a button to press — just in case.