How connect 2.4ghz devices to new modem?

The issue you're likely hitting is Smart Steering. By default, the modem combines the 2.4GHz and 5GHz bands into a single network name. Here's something you can try:

1. Go to 192.168.1.254 in a web browser on a device already connected to your Wi-Fi network.

2. Use the Admin username and password found on the sticker of the side/bottom of the modem.

3. Click on the Wireless Setup tab at the top.

4. Find the 'Smart Device' section in the left hand menu.

5. Set the Smart Device Network to Enable. (also note the unique SSID (network name) that appears...it usually adds _Smart to the current name.)

6. On whichever 2.4GHz devices you're trying to connect, look for the new "... _Smart" network to connect to it. Should be the same password.

Let us know if that works for you.