How to disable wireless on Verizon FiOS Westell 9100em and use personal router device

Here's a simpler solution you should be able to manage.

1. Disable the wireless radio on the FIOS router.

2. Assign the Linksys router’s WAN a static IP from the network of the FIOS router. For example, if the FIOS router is using the 192.168.1.x network, and has assigned itself the IP 192.168.1.1, perhaps give the Linksys router’s WAN IP 192.168.1.2. Just as long as that IP is not within the scope of the FIOS router’s DHCP server.

3. Connect the FIOS router to the Linksys router, LAN to WAN, respectively. So now they are CHAINED, with the Linksys downstream of the FIOS. Make sure the Linksys router is using a DIFFERENT local network than the FIOS. Again, assuming the FIOS is 192.168.1.x, perhaps make the Linksys 192.168.2.x, or 10.1.1.x, whatever. It just has to be different.

4. Finally (and this is optional), to make firewall management easier, place the WAN IP of the Linksys router (from step 2 above) in the DMZ of the FIOS router. This forces all unsolicited inbound traffic that would otherwise be blocked by the FIOS router's firewall, to be forwarded to your Linksys router and its firewall. Behaviorally, it's as if the FIOS router's firewall was turned off.

In a perfect world, using bridge mode would be preferred. But the above is a pretty close approximation and minimizes the amount of reconfiguration on the FIOS router (thus you’re less likely to mess something up). And you still get almost all the benefits of using your own Linksys router.

[fios router (192.168.1.x)](lan)<-- wire -->(wan)[linksys router (192.168.2.x)]