Hello, I am having same issue with ASUS Nexus 7 2012 tablet. Can't unlock bootloader to flash anything. Cannot boot Android. It happened after device received OTA update, now it has 4.23 bootloader. Tried unlock using fastboot - device freezes, nothing happens. Also tried update using adb to Android 4.3 which was previous the update - got errors with buid.prop not found, file validation.. Isn't there any good news how to force flashing on locked bootloader or unlock without device freezing? I can enter fastboot, adb (from recovery). While cleaning cache also hangs device..