Comcast XFINITY → [Firmware] SB6120 Firmware update. Modem keep rebooting

Hi,

I bought Motorola SB6120 modem sometime back but did not replace the existing comcast modem due to phone service. Now I want to replace the comcast SBC cable modem with Mot SB6120. When I connected the modem, it keep rebooting after blinking on ONLINE led many times. I searched and found the issue with firmware on the modem. Its current firmware is

SB6120-1.0.1.8-SCM02-NOSH April 22 2009

Comcast technician visited to resolve the issue, but he could not resolve the issue and gave unconvincing answer that only model sold by few vendors are supported by Comcast even if they are listed as supported modems. I asked him to give me exact specification I need for the modem to work, but he could not give any satisfactory answer, just told me that it should have D3 listed which suppose to be DOCSIS 3.0 which this DB6120 modem is. I have done the following with no success.

1. Left the modem connected for more than 24 hours still same issue.
2. Asked Comcast to remove my modem from my account and left the modem connected for more than couple of hours. still same issue.

It looks like current CTMS may be causing issue with firmware upgrade.

How do I get my modem firmware upgraded? Any help will be appreciated.

I have used following link as one of the reference

»[Connectivity] Motorola SB6120 doesn't work with CC-Resolved

Best Regards

Please register with the site and send me a PM with your HFC mac address. I can help get the firmware upgraded.

Someone came up with another workaround, which is what I assume netcool is talking about. I think something about the old 1.0.1.8 firmware not properly supporting something to do with ipv6?

That firmware does not support IPV6 or upstream channel bonding.

The fix is to make sure the 6120 is provisioned for walledgarden (walledgarden disables upstream channel bonding for this modem.) and then to also flip the cable modem to IPV4 as its trying to register.

Then it should be able to come online and update itself.

Thanks netcool. I sent you HFC mac address in PM. Are you able to send the flush the firmware. Please let me know so that I can test at my end.

Thanks a lot netcool. You really saved me. Now I can see solid online light, and I also checked that internet is accessible from the cable modem. Only thing I could not check the status of modem by going to 192.168.100.1 which I was able to see before. Is the base address changed due to firmware update.

Thanks a lot again for you saving me from lots of trouble.

Best Regards