AC66U - 3 leds - bricked?

Hi

I have an issue with my AC66U - during startup LAN1, LAN2 and WAN LEDs are still powered on, and stays like this all the time, After some time 5G interface brings up, and that's the only way I can access router. It's not possible using LAN/2,4G - they do not work. I can access router via GUI and telnet. Reflashing firmware doesn't help here. I cleared also NVRAM using telnet but still no joy.

any ideas appreciated.

thanks!