How to hide the boot message - "doing fast boot" ?

I want to make openSUSE to boot more quiet , and build grub2 with some quiet patches.
I also add the kernel line plymouth:force-splash to grub2, but it doesn’t work. Just like Plymouth broke to text when I use e4rat.

I find another boot message “Creating device nodes with udev” is in the file /lib/mkinitrd/scripts/, but I don’t know which file show “doing fast boot”?

OK! although I can get few help. I solve this problem by myself.

sudo sed -i "s/echo\ \"doing/\#echo\ \"doing/" /lib/mkinitrd/bin/linuxrc sudo sed -i "s/echo\ \"Creating/\#echo\ \"Creating/" /lib/mkinitrd/scripts/ sudo /sbin/mkinitrd