The Pixel 4 is the first phone to ship with Soli-powered Motion Sense gestures, but the Soli radar chip shuts off when the phone is used in restricted countries. The reasoning is quite simple — radar technology can potentially interfere with navigation systems and military equipment, so Soli needs explicit approval from governments. Unfortunately, the number of countries where Motion Sense works out-of-the-box is quite small. We suspected it was only a matter of time before someone figured out a way to bypass the regional restriction, and today's the day.
Motion Sense uses radar to identify and interpret hand gestures, allowing you to control some select apps and features. Although it's little more than a party trick right now, it has the potential to branch out into more areas such as gaming with developer support. Of course, Google has to let developers access it first. That didn't stop a Redditor from poking around in the Motion Sense APK, eventually discovering a root-only method to enable the feature regardless of location. After enabling "Developer options" on the phone, simply connect it to a PC with ADB and enter one of the following commands.
Alternatively, you can arrive at the same result by using Magisk and an Xposed module called EnableSoliOnPixel4. Several XDA Forums users have confirmed Motion Sense is working in restricted countries like China and Mexico with the module.
Just because you can do this doesn't mean you should. Using Soli in unapproved countries probably runs afoul of local laws, and you need to be extra security-conscious with a rooted phone in the first place.