Its very unlikey too, but there is allways a chance, very very very very low chance.
Iv allways tried to keep my mobo's as upto date as possible, and have yet to have any issues, but there is allways that chance, no matter how minisucle it is.
But there really is'nt anything to worry about, aslong as u do it the right way, and don't interupt it, when its updating everything is fine.