I've had a Tivo Premiere XL for over a year with no issues via a Comcast CableCard. Starting on Friday noticed that it started rebooting by itself. Coincidentally noticed that our Comcast set up box had issues with On Demand the same day and had to power it down and back up to get it working. Tivo now seems to be rebooting every 5 to 15 minutes. I've tried various things including disconnecting all cables except HDMI input to the TV , but through stepwise trial and error seems oddly enough to be related to having an extended cable channel lineup vs. basic cable channel lineup. I'm able to view all channels through basic channel lineup through the CableCard without reboots occurring, but has the annoying side effect of no scheduling information for channels not in the basic channel lineup. And unit even seems to exhibit this behavior with extended lineup with the CableCard unplugged. Contacted Tivo and Comcast support and gave the background on this and worked through various Tivo and CableCard checks but with no luck. At this point looking at getting a replacement Tivo warranty unit, but trying to rule out any possible configuration issue. Just seems odd that extended vs. basic cable channel lineup seems to cause reboots to occur (with or without the CableCard plugged in). I guess it could be failing hardware, but figured I'd check anyways. Also wondering if something possibly changed with Comcast (asked the Comcast rep and indicated what had happened with our setup box for On Demand on the same day), but no luck there. Has anyone seen anything similar in behavior and anything else to check? Appreciate any help. Thanks.