C3700-NAS factory reset won't connect to Comcast Xfinity

[720eugene]

I was using this modem/router with Comcast/Xfinity until Aug 2017, at which time I disconnected it and performed the factory reset.  Now Feb 2018, I cannot get it to connect to Comcast/Xfinity anymore.  Is it due to the old firmware applied at factory reset?  How do I get it to connect now, since only Comcast can push firmware, but it won't connect?

[antinode]

> [...] Is it due to the old firmware applied at factory reset? [...]

   A reset operation resets the settings, not the firmware.  Does the
router's web site report a different firmware version now?

   If you had the C3700 configured to report a non-default MAC address,
then a reset could spoil that.  Have you talked to Comcast?

[720eugene]

I've spent quite a bit of time with Comcast reps on the phone - even to their Level 3 - with nothing working in the end.  They could see that something was connected to the line, but were not able to push any signals - reset, etc.  The device currently has Firmware 1.01.05.  The Netgear site indicates the Firmware with Comcast should be 2.02.17, but now I have now way to get that - even to see if that allows the device to connect.

[vkdelta]

Comcast pushed new FW to pretty much everyone last year. If you had disconnected during that time, you would not have recieved updates.

1.01.x is very old FW for Comcast and Comcast have modified their systems to make 1.01.05 incompatible. 

Please pm me and I will see what can be done..

[michaelbo]

I'm having the same issue. Dropped VK a private message. My firmware is a *tad* newer at V1.01.11, hardware version is C279T00-01. Comcast phone reps couldn't make it work. Field tech checked signal strength and could not do anything further. (Very good signal...) Help!