At the very least you would expect these images to be signed. There's no way code should be injectable on the floor. The boot loader would simply not accept it.

At the very least you would expect these images to be signed. There's no way code should be injectable on the floor. The boot loader would simply not accept it. And you would expect any signed images to be code reviewed, regression tested, and system tested. Still, no way for sabotage on the floor.