Evidently there's more than one way depending on the firmware. If one doesn't work he might try the other.
https://support.google.com/googlenest/answer/6246619#Factory%20reset%20button&zippy=%2Cgoogle-wifi-p...
Factory reset your router or point with the factory reset button on your device
Nest Wifi router Google Nest Wifi router
The factory reset button is located on the bottom of the router. Check for a circle etched into the bottom.
Press, then hold the factory reset button for 10 seconds. The light will flash yellow, then turn solid yellow. When the light is solid yellow, release the button.
This starts the reset process, which can take up to 10 minutes. Don't unplug the power cord during this process.
When factory reset is complete, the light on your router will pulse white.
After the device has been reset, the device will still appear in the Google Home app. To remove the device, follow the instructions for app factory reset. To set up again, you’ll need to create a new network, then add any points again.
Note: If you hold the button for too long (>15 seconds), the device will start flashing yellow and won't factory reset. In this case, unplug the power cord from the device, leave it unplugged for 1 minute, and then plug the power cord back in and try again.
The hardware button factory reset will delete all current settings and data from your device. However, all data Google has collected and analyzed for Cloud services will remain. After 6 months, Google will automatically delete this Cloud data. You can always remove this data by performing a factory reset from the Google Home app, even on the offline network.
Nest Wifi point Google Nest Wifi point
The factory reset button is located on the bottom of the point. Check for a circle etched into the bottom.
Press, then hold the factory reset button on your point.
After about 5 seconds, your device will begin the factory reset process. Continue to hold the button for about 10 seconds, until there's a sound confirming the device is resetting.
After the device has been reset, the device will still appear in the Google Home app. To remove the device and your previous network, follow the instructions for app factory reset.
The hardware button factory reset will delete all current settings and data from your device. However, all data Google has collected and analyzed for Cloud services will remain. After 6 months, Google will automatically delete this Cloud data. You can always remove this data by performing a factory reset from the Google Home app.
Google Wifi point Google Wifi point
Important: If you use the Google Wifi app to manage your devices and factory reset your router or points, you’ll need to use the Google Home app when you set them up again. Learn more about changes to the Google Wifi app.
The factory reset button is a circle etched into either the bottom or back of the device.
Press, then hold the factory reset button for 10 seconds. The light will flash orange, then turn solid blue. When the light is solid blue, release the button.
This starts the reset process, which can take up to 10 minutes. Don’t unplug the power cord during this process.
When the factory reset is complete, the light will transition from solid blue to pulsing blue to indicate it's ready for setup.
After the device has been reset, the device will still appear in the Google Home or Google Wifi app. To remove the device and your previous network, follow the instructions for app factory reset.
If the firmware on your Google Wifi point is earlier than 13729.57.27:
Unplug your point from the power source.
Press, then hold the factory reset button on the device. While holding down the button, plug the power cable back in. Continue pressing the button for about 10 seconds. Your point will flash white, then blue. When it flashes blue, you can release the button.
The point will continue flashing blue for about 45 seconds, then it'll turn solid blue. This process can take up to 10 minutes.
Wait up to 10 minutes for the device to fully reset.
Once complete, your point will pulse blue to indicate it's ready for setup.
After the device has been reset, the device will still appear in the Google Home or Google Wifi app. To remove the device and your previous network, follow the instructions for app factory reset.
If you have reset your primary point (router), you’ll need to set up a new network and add any points again using the Google Home app.
Note: If you hold the button for too long (>15 seconds), the device will start flashing orange and won't factory reset. In this case, unplug and try again.
The hardware button factory reset will delete all current settings and data from your device. However, all data Google has collected and analyzed for Cloud services will remain. After 6 months, Google will automatically delete this Cloud data. You can always remove this data by performing a factory reset from the Google Home or Google Wifi app.
