Upon bootup, when /etc/init.d/udevd is run, 70-persistent-net.rules should be
populated with the still unnamed ethernet devices. This does not happen, since
the same init-script just calls 'udevadm trigger', which defaults to
'--action=change'. 75-persistent-net-generator.rules though handles only
events with ACTION=="add", and so never comes to action.

I've fixed the issue on my system by enhancing /etc/init.d/udevd:

ebegin "Populating /dev with existing devices through uevents"
if yesno "${coldplug}"; then

1. perform full coldplug:
   udevadm trigger --action=add
   udevadm trigger --action=change