COX says to call Netgear - Netgear says to call COX

Yes, there are "Some" ISPs that don't update "user owned" modems. ISP owned yes. This varies from ISP to ISP. 

The reason why users are not allowed to update FW is that this has been a DOCSIS policy standard for many years. Please, contact the DOCSIS community developers and post your concerns there. They are in charge of how cable modems operate.

One reason why it came about is that Cables ISPs early on didn't have good testing methods in place for testing new modems and FW out. I'm sure there was some non communication handling as well between modem mfrs and ISPs. Modem mfrs would just hand out FW to the ISPs and thinking that the modem mfr was doing due diligence in testing, ISP would push FW to user owned modems and either bugs caused problems or the push would brick the users modem. Thus incurring costs for the ISP to replaced the user owned modems. So due to this, ISPs are now responsible for testing any new FW that the mfr hands them prior to pushing to ANY modem. However 'some' cables ISPs took the stance of to avoid any kind of modem liability, 'some' cable ISP will NOT update user owned modems period. They will only push to ISP owned modems. Not all cable ISPs take this stance. Apparently Cox does. I know Spectrum is another that seems problematic for users owned modems. 

If your modem isn't locking in on channels, there maybe a signal line or cable line problem rather a FW issue. Not everything is fixed by FW. 

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-Modems/m-p/1530376#M12853
https://www.duckware.com/tech/solving-intermittent-cable-modem-issues.html

For ISPs that just won't update user owned modems and users seem to have problems with the modems they buy, we recommend to avoid the hassles and use the ISP owned modem, even if you have to rent it. 

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Cox-Me-Nitgear wrote:

[quote]ALL Cable ISPs are responcible for updateing FW ON ALL cable modems. There NO user modems that users can udpate, sans CAX series which users can update the router side of this product. The modem side still requires the cable ISP to update the modems FW. No exceptions.[/quote]

Well, here in Mesa Arizona things are different. Cox ** DOES NOT ** push updates on 3rd party modems.
We've been down the rabbit hole of questioning our router(s) and devices(s), sorry. I trust our Cox FSE who showed us exactly what was going on at the modem. Forget the router. Our Netgear CM1200 could not lock on the downstream signal while his monitoring device had no problem whatsoever. We repeated the test several times, same result.
We own this modem and I think that we should be able to push our own updates, as Cox is telling us to do. So why is Netgear not allowing users to update? [Head scratcher].
So… we went with Cox Panoramic Wifi solution. We should have the hardware in a couple days. We are keeping our CM1200 for now until we get comparative test results with the Cox device.

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