I've tried to update over Wi-Fi and it didn't update at all. So I'll be updating via USB which is fine with me.Bricking is when an electronic device gets messed up so badly, it can't be restored.
In other words, its now a brick to use as a paperweight, door stop or in a cool wall design.
A normal wifi update shouldn't brick it. I'd only done it once but it downloaded the entire package before installing.
However, if the power is shut off during the installation process, you do run the risk becasue it won't know what to do with itself.