Orbi RBS850 not connecting to RBR850

Hi all,

Not sure if this is the right place for this post.

Purchased Orbit rbr850 & rbs850 in one pack first.

Then purchased another three rbs850 separately.

It works fine before.

Suddenly not working after power outage. The issue is the later three rbs850 cannot connect to the rbr850.

I tried below so many times:

Reset rbr850 and all rbs850

Set up new system.

The original rbr850 and rbs850 are connected and works but the later three rbs850 still not connecting.

I am thinking this might be different firmware in the later three rbs850.

So questions:

1. How can I connect the later three rbs850?
2. If update firmware to the later three rbs850, how can I do it if not connected ?

Thanks all.