I had the same problem. but you can solve it.
It's a problem of network configuration, fonera+ has a switch and need a different configuration.
I follewed the suggestions of Lama Bleu (http://www.moliets-bastide.info/).
I paste here his method:
I think the problem is by default OpenWRT is using eth0 and eth1 as
LAN ans WAN interfaces. But for fonera+ we need to access eth0.0 and
eth0.1 ports.
I'm not sure it's the problem, but I think yes.
The other solution if you have some free time today, is to boot
FONERAM (working in RAM, no reflashing needed) and try to access the
JFFS partition, using "mtd-mount" command.
Then you can access/edit the /jffs/etc/network file to check if LAN is
on eth0 or eth0.0
If you have few minutes today, go to
http://www.moliets-bastide.info/post/FONERAM
Intructions are easy to use ( How to run section), and the you can
access the actual "rootfs" partition.
(I followed the guide on his site and I mounted the jffs partition with mtd-mount but he also suggest this way):
To mount the JFFS (very long, perhaps 3 minutes):
root@LamaBleu:~# mount -t jffs2 /dev/mtdblock1 /jffs
(when you hat it mounted)
then perform this command (backup and replace network file):
cp /jffs/etc/config/network /jffs/etc/config/network.org
cp /etc/config/network /jffs/etc/config/network
and now the switch will work properly!
if you also want to active the wifi device you have to edit :
/jffs/etc/config/wireless
than reboot and enjoy it!