[Update: Fixed by Factory Reset] Some Google Pixel 2 Owners are Reporting a Bootloader Unlock Bug
The Pixel 2 and Pixel 2 XL are flagship devices meant to showcase the Google software experience. But the phones have had their share of issues, ranging from the Pixel 2’s inability to flash factory images and OTAs and high-pitched earpiece noises to the Pixel 2 XL’s display burn-in and audio recording issues.
Unfortunately, the problems haven’t stopped there. Some Pixel 2 owners who purchased their devices from the Google Store are reporting an inability to unlock their phones’ bootloader.
The problem stems from the OEM Unlock setting in Developer Options. The toggle is greyed out, making it impossible to enable. Affected devices show a prompt to connect to the internet even when the phone has an internet connection, or suggest that the user contacts a service provider.
Google customer service representatives were unable to confirm whether the problem was a hardware or software issue.
Only a small fraction of users have reported the issue, so it doesn’t seem to be widespread. Curiously, though, most ordered from the Google Store and had their Pixel 2 delivery postponed by as many as three weeks. Some speculate that Google inadvertently shipped bootloader-locked Verizon models to these customers.
There isn’t a do-it-yourself fix outside of returning your phone back to Google and asking for a replacement. Users report that factory resets and flashing factory images using ADB sideload had no effect.
If you are experiencing the issue, head to the Google Bug Tracker to star it and add a comment.
Update 11/21/2017: This issue has now been fixed. All it takes for users to now unlock is factory resetting the phone and connecting it to the internet for the initial setup.
Marked as Fixed. Please factory reset your device and make sure it connected to the internet during setup as this issue has been resolved.Factory Reset: Settings -> System -> Reset Options -> Erase all data (factory reset).
Thanks to XDA Senior Member bunklung for the tip!