As with any operating system update, if you don't do it exactly right you risk the possibility of trashing the instrument. This is true of computers or keyboards or any item that has updatable flash ROM.
Therein lies the real danger!
No matter the quality of the software update, if you goof, your in one big mess of trouble.
Of course, no permanent damage is done but it might take a factory instructed procedure to straighten it out. If I remember right, Eddie Williams helped out someone in that trouble last year.