SamyGO

You can find uImage in archive you have downloaded already. Check boot directory for it. You have to place uImage to fat32 partition of your bootable USB.

But if you are a bit risky and you have fully functional u-boot ( i see you have restored your u-boot with right one - you always can repair your TV if something fails), i suggest you to do only step3 from this manual: flashing firmware i attached there, changes kernel on your TV with one from arris69 with network support permanently.
If you can`t boot TV after that (im almost 100 sure that everything will be good), you restore TV easily, i can guarantee it for you (off cource if you follow instructions )

Yes. Now your kernel supports network.
Here are some issue reported - after set Network support to wireless in settings menu (you have to do it too), there was no network settings window on TV. Then required settings you need to enter manually or with help of script.