Firmware update for CM400

I hope this helps other people reading this thread.  After spending 3 hours going back and forth between Netgear and Comcast, I learned that Comcast will do a firmware push if you just request a modem reset.  Apparently, a modem reset will automatically push the latest firmware version to your modem.  If you explicitly ask for a firmware push, the agent may not be knowledgeable enough to know that they can accomplish this through a modem reset as opposed to something more explicit on their end.  That's when they will tell you it cannot be done.