@Saransk93 

Thanks for reaching out. I understand that you want to upgrade your existing Deco Mesh system by replacing your current main Deco unit (which is connected to your FIOS router via Ethernet) with a new Deco XE70 Pro unit, and you would like to know how to change the main Deco in this setup.

Here’s how you can change the main Deco unit to your new XE70 Pro while it is connected via Ethernet to your FIOS router:

1. Setting a new Deco unit as the main Deco:
• Power on the new Deco XE70 Pro unit and wait until its LED starts flashing blue.
• Open the Deco app on your phone or tablet.
• On the main page of the Deco app, tap the "+" icon in the top right corner.
• Select "Replace Main Deco" from the menu. The app will begin searching for the new main Deco unit.
• Follow the on-screen instructions in the Deco app to complete the process.

Important Notes:
• Make sure your phone is connected to the Deco Wi-Fi network during this process. Otherwise, the option to switch the main Deco may not appear.
• Ensure you are logged in as the "Owner" of the Deco network, not just as a "Manager." If you don’t see the "Set Main Deco" or "Replace Main Deco" option, try quitting and reopening the Deco app.
• When you switch the main Deco, the WAN MAC address will change. You may need to reboot your FIOS modem/router to allow the new main Deco to access the internet.
• This method works only if your current main Deco is functioning properly. If the main Deco is offline or faulty, you will need to reset the entire Deco network and set up the new XE70 Pro as the main Deco from scratch.

If you need a detailed walkthrough for setting up a new Deco system, you can refer to this FAQ: https://www.tp-link.com/en/support/faq/2464/

Let us know if you have any questions or need further assistance!