Square Lock Boxes can be found in the Castle area in Resident Evil 4 Remake. Here's how to open them with the Cubic Device.

With the lock box cover plate secure insert the key into the hole. Turn the change key in the proper direction- left or right depending on lock box mounting position.

The Resident Evil 4 square lock boxes in the Castle section need a special key called a Cubic Device, and you won't be able to open them without it. It's definitely worth doing - those five square ...