Comment 9 for bug 1193161

it could either be that there are udev rules that recognize the device on the USB bus but have no special rule to handle rmnet, or that the device specific rules file is run to early

a) try to move /lib/udev/rules.d/75-net-description.rules out of the way for a test ...

b) if a) improves anything, try putting it back and move /lib/udev/rules.d/70-mako.rules to run after 75-net-description.rules (i.e. move it to 80-mako.rules)