- Your device has to be unlocked, otherwise you are out of luck, I believe (who knows, maybe something can be done using ADB debugging only). Note how unlocking your device makes it less secure.
- Power+VolumeDown until in fastboot mode.
- fastboot flash recovery recovery-clockwork-188.8.131.52-grouper.img
- Go to recovery mode without rebooting, which may reset recovery.
- $ adb shell
- $ mkdir /mnt/d && mount -t ext4 /dev/block/platform/sdhci-tegra.3/by-name/UDA /mnt/d
- $ rm /mnt/d/system/locksettings.db*
- $ reboot
It is probably possible to modify the settings in locksettings.db individually, though it didn’t work for me on first attempt.
Note: When profiles are used, the data for other users can be found in /data/user/.