If you’re on the Android 8.1 Developer Preview right now, consider setting a PIN lock for your device before you decide on a factory reset.
One Redditor, Tom Bolger, encountered an issue with AT&T services while on the Android Beta Program and, for some reason, forgot his unlock pattern. As Find My Device is not able to unlock the device remotely, Bolger decided to go through a factory reset and enter his Google credentials. Instead, the device booted and asked for the “previously used secret” and stuck to a PIN, not a pattern. An attempt to flash an image was unsuccessful as it produced an unknown fastboot error.
First of all, forgetting your PIN and then asking for it after a factory reset helps nothing. Complicating the fault further is the fact that the user could not specify a pattern at that stage — is there a code equivalent that could be used? Google support acknowledged the issue and has authorized an exchange for his Pixel 2 XL.
It was pointed out that Pixel C owners have been troubled with the seemingly randomly striking bug in which their devices forget the pattern lock that was set. Google has also acknowledged this as a “high priority” issue. We would presume with the combination of these two fail-deadly issues that Pixel C users should be discouraged from entering into the beta.