According to experts on the factory mail lists, "splash=*" is no longer parsed:

Cristian Rodr��guez:
JFYI: The kernel does not parse this option at all. CONFIG_BOOTSPLASH
patches are long gone.

since kernel 3.10-rc1 according to the log

Michal Kube��ek:

... Version 3.10 falls between 12.3 (kernel 3.7) and 13.1 (kernel 3.11).



However, the installation system uses:

splash=silent quiet showopts.

Also "showopts" is not used by grub2, only by grub1 which I believe is not
supported. Both splash and showopts should go, IMHO.