Currently, even if the 'udev-cache' package is added to the image, it actually has no effect. The logic in the udev and udev-cache init script has some problem, causing the cache not created at boot time. This should be fixed for both sysvinit based system and the systemd based system.
merged into poky/master: 9d68aa5e3590c8eefb221f62b0390a05061a756a http://git.openembedded.org/?p=openembedded-core.git&a=commit;h=84e0ec2e677fb0236a38478372cdd75797cf5a2e