I have an RBR850 with an RBS850 satellite

While this is an old post, I'd like to point out my experience with this set up as of March 2026, for those that may have the same problems. 

I have an RBR850 with an RBS850 satellite and this has been running great for about a year now. I just bought a second hand RBS350 on the basis of the Netgear post saying it was compatible. After a day of trying different things and pulling out my hair in frustration, I found it actually is still compatible. HOWEVER, you need to look at the 'Previous Versions' in the firmware section and look for the, at the time of writing, latest firmware 7.2.8.2! It's hidden away and not in the correct order. Flashing this to the RBS350 and the unit works perfectly now with an ethernet backhaul (connected via wireless backhaul initially and then swapped out). Updating the firmware was a learning experience to itself, since on mine I couldn't access it via a web interface it had to be done via command line with a wired direct connection to the RBS350.