If science found a way to download all things from your brain and place it in a computer, it will not be you. You will still be in your body but a copy of your mind is on a computer.
The only things I can think of that makes you, you is your specific hardward.
The specific brain cells you were born with. The specific way they communicate with each other. All these give you a unique I.D that can only be the consciousness of you.
My other thought was that you have a specific energy I.D that give you the consciousness that is you.
I don’t know. What do you think?