@David-TP As far as I know, 165 cannot be rolled back once installed, at least that's the warning it gave before I installed it at the time. This is different if someone uses lets say a laptop or...

@Dutchbear80 all internet connection is lost, that's correct, ziggo confirms the router can no longer be accessed by them when this happens. The deco units themselves remain working normally, except...

M4 v2, updated to 165. setup is as follows, router (ziggo black smartwifi with WiFi disabled) 1 cabled to main deco set up as access point, in turn wired to second deco upstairs. Second deco has 1...