now my yaboot.conf looks like
init-message="Welcome to Fedora!\nHit <TAB> for boot options"
(I have removed as you suggested rhgb from the beginning of the append line)
but the graphical boot is still on.
May be this is dued to the fact that I use kboot for starting my PS3
BTW: there isn't a file kboot.conf as in the past YDL5 distribution I used to modify, now the filesystem hasn't kboot.conf.
How can I do?