CM1200 useless on Charter/Spectrum after they enabled OFDMA on upstream channels

[ctem81]

Purchased a CM1200 modem a few months back to use with my spectrum service.  Has been working fine for the last 3 months with OFDM on the downstream channels and regular upstream bonded channels.  About 2 weeks ago spectrum switched my area to upstream OFDMA channels and immediately the modem became a brick.  It syncs partial service for both DS and US.  T3 timeout errors like crazy in the modem event log.  Switch back to my trusty D3 arris SB6183 and all works fine again.  

Realzing this was not a plant issue or local issue in my home after reading about other people having the same I went ahead an opened up an FCC complaint with spectrum to see what could be done.  After troubleshooting a tech at spectrum and him escalating they basically said it was a netgear problem and to check with netgear on progress of a potential firmware update to be deployed for this modem.

Anyone know if netgear has a firmware update planned for this model?  I would have just returned the damn thing but I am beyond my return window as the modem worked flawlessly for 3 months until OFDMA was turned on in my area.

Thanks

[ctem81]

Additional photo with errors.

[FURRYe38]

Try a factory reset on the CM modem. Also disable LAG on the modem. 

@vkdelta 

[ctem81]

Factory reset already done and LAG is not in use.  

Spectrum said netgear already knows about this issue and is working on a fix.  trying to figure out the timing of the new firware release.

[FURRYe38]

Well CC and XF ISP got v2 FW update this past month. I presume all the rest are forth coming. NG doesn't make it know when they will push to ISPs though. So you'll have to keep in contact with your ISP about this as they are the ones the can only update FW on modems. 

Good Luck.

[vkdelta]

pls DM me

[Draco]

Any motion with this and Spectrum? I'll also DM you just in case there's something I can do or test... because this just recently started happening to me as well. Endless T3 and T4 timeouts, causing eventual connection instability/intermittency.

[FURRYe38]

Please post a copy and paste of the modems connection status page.
Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.
Be sure there are no coax cable line splitters in the between the modem and ISP service box. 
Be sure your using good quality RG6 coax cable up to the modem. 

https://community.netgear.com/t5/Cable-Modems-Routers/General-info-and-Troubleshooting-for-Cable-Mod...

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@Draco wrote:

Any motion with this and Spectrum? I'll also DM you just in case there's something I can do or test... because this just recently started happening to me as well. Endless T3 and T4 timeouts, causing eventual connection instability/intermittency.

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[ctem81]

I have two contacts at netgear who worked on my behalf to get my own modem upgraded to firmware version 3.02.01.  Charter should be making 3.02.01 the new default version for anyone using a CM1200.  They are dragging their feet and not responding to my repeated emails.  It is very frustrating.  I have threatened another FCC/BBB complaint as others are now reaching out as they enable OFDMA in more markets across the country.

[Draco]

Interesting. Well here's hoping I can eventually get that done. This a user-initiated thing or something done on Spectrum's end?

Hardware Version	1.01
Firmware Version	V1.02.01

[Draco]

Well after A LOT of reading on this same issue with threads even you replied to, I feel bad even bumping this thread to the top!

Shame on Spectrum for holding out this long. I wish I knew when they did this "upgrade" and it sounds like I need to dig down deep to get it fixed. Sad.

For anyone else coming across this thread feel free to read up here instead:

https://community.netgear.com/t5/Cable-Modems-Routers/CM1200-hell-on-Spectrum/m-p/2021147/highlight/...

https://www.dslreports.com/forum/r32832397-Netgear-CM1200-is-now-crap-OFDMA-just-enabled-on-upstream

Guess that FCC/BBB report is in order.

[FURRYe38]

Ya, It's up to ISPs to test and push FW updates that are recieved from the modems Mfr, i.e. NG in this case. NG can only do so much. Shame that some ISPs behave like this. 

[Marksa17]

Sorry revisiting this thread as I’ve just recently had the same issue. Been back and forth with spectrum and they are telling me it’s an issue with docis 3.1 and want to flip out my modem with theirs. You were able to have them push out a firmware update? Netgears site has listed the v 1.02.01 for spectrum updated firmware. Who/how did you get them to update to 3.02.01. I feel like I’m going to call and say upgrade and they are just going to do no dice. This seems like it’s been an issue for years where ofdma upstreams are being used. Any help would be greatly appreciated

[ctem81]

I was able to get two contacts at netgear who coordinated with spectrum and pushed the newer firmware out to my modem and exempted it from being downgraded.  I will PM you their email addresses.  They are well aware of the issue and pushing to get the firmware approved for system wide deployment to all users running the CM1200

[ctem81]

Received confirmation from Charter that the new firmware has been approved and was handed off to APODID – Device Operations on 6/10/21.

They have started pushing to owners of the CM1200 and plan to be finished rolling out to all by 7/9/21. Please advise if you receive the update. Version should be 3.02.01.