Is the problem solved? I think that a quick test is opening a terminal and issuing:
su -
<root password>
modprobe rndis_host
and then connect your phone and test.
If it works, to make the change permanent you have to comment out the relevant line in
/usr/lib/modprobe.d/50-blacklist-rndis.conf
so that it reads:
# blacklist rndis_host