I have a similar issue when booting my x86_64 HTPC from a 16GB USB flash drive. Network is connected but still no internet, and even setting "wait for network option" doesn't help. I can SSH in to LE, even ping the machine, and from SSH on LE I can ping the outside world and curl to my heart's content, but inside Kodi itself the internet connection just doesn't work with no indication of a problem in the logs. Switching to a 2GB SD card or a different 8GB USB flash drive works.
This actually happened to me on 2 different HTPCs with 2 different motherboards produced by Gigabyte. So maybe it's a Gigabyte motherboard thing.
Sorry to change the topic of this thread, but if anybody has any ideas why this would be happening please chime in.