Actually, I think it makes more sense to use the SPLASH_BIN variable set by this script.
--- bootsplash-3.3/debian/patches/initramfs.dpatch 2007-04-20 08:18:23.000000000 -0600 +++ bootsplash-3.3-new/debian/patches/initramfs.dpatch 2007-04-20 08:19:09.000000000 -0600 @@ -59,4 +59,4 @@ + exit 0 +fi + -+splash -s -f $SPLASH_FILE > $DESTDIR/bootsplash ++$SPLASH_BIN -s -f $SPLASH_FILE > $DESTDIR/bootsplash
