@iiee Firmware version 1.2 should have Connection Preference feature, which you can use to force Samsung A9+ tablet to run on 2.4GHz band. See Part 2 of the following document: How to select a...

@FMDK Open Deco app, check Main Network settings and if it is set to hidden. Also check all other settings: SSID and such. You don't need to have smartphone with Deco app connected to Deco WiFi to...

@Baggers82 You can connect powerline adapter to Main Deco, but you can also connect that powerline adapter to any of Satellite Deco in the house. If you find that powerline link is better when in...

@saltis99 I just thought about something else you could try first. Maybe WiFi connection specifically to Main Deco will be enough. Power off all Satellite Deco, so that only Main Deco is running, and...

@saltis99 This tool has about 80% success rate. Unfortunately, it is the only way to update Deco M9 Plus with firmware 1.2. Some people had success with Update Tool when they wired PC with Ethernet...

@saltis99 Shouldn't utility say "Deco M9 Update Assistant?" Did you follow correct link to download utility for M9 Plus (second link, not first that is for M5)?