One of the nice things about Google's phones has always been that you could unlock the bootloaders to flash ROMs or official system images. However, Verizon isn't cool with that, so Pixels sold by the carrier don't support bootloader unlocking. Or do they? An XDA poster has discovered a method for unlocking the bootloader on first-gen Verizon Pixels, and it's not even very complicated.
All you'll need to get your Pixel or Pixel XL unlocked is a computer with ADB running. Remove your Google account from the phone, take the SIM card out, and reset your device (after backing up, of course). When it reboots, skip the entire setup process—don't even connect to WiFi. Then go into the settings and enable USB debugging. Next, you'll need to connect the phone to your PC and use the following ADB command.
adb shell pm uninstall --user 0 com.android.phone
After that, you may need to wait a few minutes, but the OEM unlocking toggle in dev options should become active. Toggle it and reboot into the bootloader. You should be able to use the "fastboot oem unlock" or "fastboot flashing unlock" commands to unlock the bootloader.
This method should work on the latest Android 8.1 build as well as the P developer preview. Enjoy.
- XDA Forums