Are you talking about registering / activating a modem for service with Comcast ? If you are talking about needing a firmware update for an existing modem already in service, the Comcast system automatically keeps the firmware updated with the latest loads from the manufacturer.
Years pass by and nothing has changed with COMCAST/XFINITY,
Well none of the XFINITY customer service people know about the firmware upgrades for the DOCSIS modem and they keep on saying reach out to the manufacturer (netgear).
Is there any one who can help me setup my Netgear C6300 modem with comcast?
I hope all is well. I wanted to reach out to see if you are still in need of assistance?