@databoogy I know this is an older thread - but just had the same issue. Seems like I'm going to have to hard reset the Deco and start over. This will be a colossal pain! What is going on with this...

There appears to be a way to reserve the address for the gateway (or main) router, but the other 2 get their addresses via DHCP and I'd like to reserve those as well. Is there a way to lock them...