Re-locking the boot loader

I think I have done a silly thing - re-locked the boot loader.
Now I can’t unlock it again to restore the recovery image.

Does anyone know how to force fastboot to unlock?
Does anybody know why re-locking the boot loader would do this?

Why did I re-lock the boot loader? Well, when I was booting into a custom image there was a message on the boot screen warning me that the boot loader was unlocked and I was wondering if that meant I should lock it again. So I did. It seems that it was a bad idea.

Same here. After re-locking, I can’t unlock my ShieldTV again. Anyone resolved this issue?

n@ubuntu ~/shield $ fastboot oem unlock

(bootloader) Device cannot be unlocked.
OKAY [ 0.017s]
finished. total time: 0.017s

Hello everyone,

today I faced the same problem, the bootloader cannot be unlocked, neither using the menu shown on the TV, neither using fastboot oem unlock.

I always get back Device cannot be unlocked error message!

Please, tell us what we need to do, we need to overcome this to flash the recovery image!!!


I am not a “Shield expert” but this document might be helpful.

Hello @TomK@Nvidia,

thank you for the information. Unfortunately I already followed it without success.

I ended up opening the Shield and connecting its hard drive to a SATA port on my PC: I found out the hard drive is completely empty!!! The partition table has gone and so all the data in it! Everything just got wiped/corrupted after the last update I received and so this is why the recovery tutorial doesn’t work, bootloader can’t be unlocked and so on.

The Shield just got bricked after an update! That shouldn’t happen but happened and my warranty already expired! :(


Sorry to hear this. Try posting your issue over in the ShieldTV forums. Maybe someone there has some experience dealing with this type of failure.

@Tom thank you for your hint, I will follow it.