When building my own dban image I was getting an error from rcS where it couldn't find the udevd daemon. It looks like udevd is not in the path where rcS can find it. Here is my patch to get it to work
[root@thbuildme01 data]# diff -u dban-2.2.8.orig/buildroot/target/device/geep/dban/skeleton/etc/init.d/rcS dban-2.2.8/buildroot/target/device/geep/dban/skeleton/etc/init.d/rcS
--- dban-2.2.8.orig/buildroot/target/device/geep/dban/skeleton/etc/init.d/rcS 2014-04-15 09:30:15.968059446 -0400
+++ dban-2.2.8/buildroot/target/device/geep/dban/skeleton/etc/init.d/rcS 2014-04-15 07:47:26.101806953 -0400
@@ -100,7 +100,7 @@
fi
[ -n "$verbose" ] && echo -n "Starting the udev daemon... "
-if udevd --daemon
+if /lib/udev/udevd --daemon
then
[ -n "$verbose" ] && echo "done."
else