Default setup, just after factory reset. Login, connect to wifi as a client. There we go, we suppose to have internet. And we do. I can ping, name resolve trace route from the router, inside network/diagnostics.
However, when I connect LAN cable to my computer, I do get IP address, default is 192.168.1.xx.. However, I can not ping anything on the internet. I can't even reach the router to which wifi is connected.
frollic gave me a hint. I've been putting wwan into lan fw zone, as soon as I put into wan fw zon it started working.
Tho, it's on it's own subnet, 172.16.1.x, while the main router is on 172.16.0.x... I believe it is impossible with this router make extended wifi on the same subnet. But it's okey.
Yea, the speed is comparatively crappy compared to my other wifi extender based on Keenetic 1 and DD-WRT. But still, this will work for me. So now I have high speed wifi in living root, kitchen, bedroom and balcony! Thanks guys!