Sure, you can&#x27;t be 100% sure of anything. In the same vein, you can&#x27;t even be sure that the world is real. The fact you can&#x27;t have 100% assurances doesn&#x27;t mean anything. What matters is how strong you make your assurances. A company having an existing system allowing for the installation of backdoored firmware is an example of something that shouldn&#x27;t be possible. It should be possible to reasonably assure that someone cannot flash something onto a person&#x27;s phone without either wiping the data or having the update signed by the user.