Both of my TiVo Premiere units updated to the latest fall update but the one connected via WiFi was having network problems.
It would pass network diagnostics and would connect to the TiVo servers but would not get account information from TiVo or go beyond that point. A reboot of the TiVo, the wireless N adapter and router did nothing to fix it. There were a number of error codes that the TiVo generated but they all seemed dubious. The bar at the top of the TiVo Central menu that normally shows ads and other thing they think you might like was blank or said that TiVo services were unavailable at this time.
The answer was to reset the wireless adapter and reconnect it to the WiFi network. Here is how to do that.
First disconnect the Ethernet cable from the TiVo and get a pointy object to hold the small button on the bottom of the adapter down (right below the Client/Bridge toggle switch). Hold it down for 2-3 seconds until the power light turns orange. Then wait a few minutes until the power light is green again.
Now find a nearby computer and turn the computer’s WiFi connection off. Then plug the Ethernet cable into the computer and point your browser to http://192.168.10.1/ .
This will bring up the guided setup wizard. Click begin setup and find let it scan for wireless networks. Once you see your network click on it and press next. Then enter your WiFi password. You can also use WiFi Protected Setup but I’ve found this to be very flaky.
Once the connection is made the wizard will tell you. Then open a new browser tab and try to surf to a website. If that works then unplug the Ethernet cable from the computer and plug it into the TiVo. Make sure the connection is firm.
Update: It seems that a factory reset of the adapter does not work for everyone. One suggestion is also to set a static IP address on the adapter (pick one that isn’t in use by anything else).