In case you have problems pairing with Firewalla, here is a simpler none automatic way to do the pairing.
Required app version:
iOS: 1.38 or above
Android: 3.3.18 or above (beta)
1. Power on Gold and connect the WAN port to the LAN port of your existing router.
2. Find another ethernet cable, connect one end to either port 1 or 2 or 3 of the Gold, connect the other end to a device having an ethernet port, such as PC or Mac.
3. Wait for 30 seconds
4. Your device should be allocated with an IP like 10.10.0.*.
5. Open browser on your device, visit the web page http://10.10.0.1, it should show a QR code.
6. Open Firewalla app, tap top-left camera, scan the QR code on the screen, then scan the QR code on the bottom of Gold.
7. Waiting for pairing to succeed and set it up like usual.
Here is the topology: