Linksys WRT1900ac v2 revert back to Linksys firmware

I have a Linksys WRT1900ac v2, I was having issues trying to install openwrt.
I am now in a situation where I cannot access the router, there are no wifi networks
being broadcast
When i connect my laptop to one of the ports in the router it says connected / no internet
checking ipconfig shows
ip address :
Subnet :
Default Gateway:

Tried to ping 1defaukt gateway get response 'General Failure;

I need to revert back to linksys firmware, how can it be done if the router is
not reachable?

If you only attempted to install openwrt once, have you tried power cycling router to force it to boot up firmware (hopefully linksys) stored on other partition?