Netgear CM3000 – Firmware v6.01.03 Causing Constant Disconnects

I had to pick up a Spectrum modem yesterday: it's free so why not have it until this is fixed. If it ever does get fixed, I can reactivate the CM3000. For now, the EU2251 that the store gave me is working and I don't see that the CM3000 has any big advantage anymore since I don't have the ping issues I had on the prior ES2251 and the modems are now free.

Just as a reminder, at least for me, you CAN get it to work eventually if you keep rebooting during the SW download INIT. You can either watch/refresh the log and when you see "SW download INIT", reboot from the Admin Home menu or wait until the online (bottom) LED is on, then wait for the two upload/download LEDs to start flashing in unison, give it about another 5 seconds, and then pull the plug and plug it back in quickly. It can take up to a dozen times doing that but eventually it'll stop trying the SW download when max retries are exhausted. As far as I can tell, then it'll stay online. I didn't leave it online longer than overnight so maybe it'd start trying again after some period but if the CM3000 is all you have, you could bandaid it like this and possibly wait for a fix.

Im having the same issue with two CM3000 brand new cable modems as the tech said it was my modem so I purchased another one and guess what…. Constant disconnects on a brand new Netgear CM3000 modem that just arrived today august 23rd from FedEx and I have no idea what is going on but Spectrum says to contact Netgear to remedy the issue with a Firmware update but when I look for an updated firmware its saying nothing is available for this modem??? What the heck is going on and I have $600 worth of Netgear Nighthawk CM3000 modems useless and using the spectrum modem until a fix is posted!! DOES NETGEAR KNOW ABOUT THIS ISSUE OR NOT????

I am having the same issue with my CM3000. There was an outage in my area about 7pm Eastern time Aug 22nd (zip 47111) and that's when my issue started. Who pushes out the update, Spectrum or Netgear? I have confirmed my CM3000 has V6.01.03 and it is doing exactly the same as the other posts are describing.

When I started digging trying to figure out what the issue was this it what came back from AI for what it's worth…:

Users of the Netgear CM3000 modem are experiencing frequent and constant internet disconnects, particularly after the modem updated to firmware version v6.01.03. This issue has been reported across multiple internet service providers, including Spectrum and Xfinity, with users noting that the problem began immediately after the firmware update and was not present on the previous firmware version v5.01.02. The disconnects are characterized by T3/T4 timeouts, ranging failures, and modem reboots, even when signal levels are confirmed to be within specifications and the modem is connected via a direct coax run without splitters. Despite troubleshooting efforts, including factory resets and bypassing routers, the instability persists, leading users to rely on provider-provided modems for a stable connection.

Firmware v6.01.03 as the Primary Suspect The most significant development is the widespread correlation between the firmware update to v6.01.03 and the onset of connection issues. Multiple users on Spectrum's network have reported identical symptoms, including the modem booting, establishing a connection, and then rebooting after completing a download, with logs showing "SW Download INIT - Via NMS" followed by a reboot cycle. This pattern suggests a firmware-specific regression rather than a problem with the physical line or signal levels. The issue appears to be impacting users across different providers, indicating a problem with the firmware itself.

Provider and Manufacturer Response The response from service providers has been inconsistent. Spectrum support has stated they have not deployed any firmware updates and directed users to contact Netgear for assistance. However, Netgear has confirmed that Spectrum controls the distribution of firmware for the CM3000, creating a communication gap between the two companies. Spectrum's engineering team has been escalated to investigate the issue, but as of the latest update, they are still insisting no firmware update was deployed and have not provided a clear path for a rollback or fix. This lack of a coordinated response leaves affected users without a viable solution, forcing them to use provider-provided modems to maintain connectivity.

AI-generated answer. Please verify critical facts.

Reached out to netgear, they confirmed that the firmware is an issue and was rolled out by our ISP. They reccommended to have Spectrum roll back the firmware to resolve the issue. In the interim I bought an Arris so my family can continue school and work from home.

So…firmware rollback possible? Netgear pushing the resolution out to ISPs to fix it.

So who do we lean on to get this rolled back because when I call their tech support they are either ignorant or gas lighting me saying that it's the OEM because they don't push out firmware updates for non-Spectrum modems. Essentially, from my point of view, Spectrum has bricked my $300+ modem and could care less.

Same modem...same issue started earlier today.

I reached out to Spectrum support again today and explained that my modem firmware was updated from V5.01.02 to V6.01.03 yesterday by Spectrum, which seems to be the cause of my internet connectivity issues. I also pointed the agent to this Spectrum community thread describing the same problem. He was very friendly, but unfortunately unable to help since this is not in his domain.

Here are the takeaways from my chat:

• They can’t open an engineering ticket for third-party modems.
• They said Spectrum isn’t responsible for firmware updates on third-party hardware.
• They believe my issue is due to “signal fluctuations” and insisted a technician visit is needed.
• They assured me I shouldn’t be charged for the tech visit since a signal issue was “detected.”

I pushed back, explaining that this isn’t a signal issue but a bad firmware push that has bricked multiple CM3000s. The agent acknowledged my concerns and said they would make a note of this community thread, but the official resolution for now is still a technician appointment or switching to a Spectrum-provided modem.

So, I’ll explain all of this to the technician tomorrow morning and share whatever I learn.

@James_M I think everyone on this thread is fully aware the Spectrum provided modems at no charge. However, most of us need better reliability, speed and capacity which is why we are willing to buy our own (expensive) modems. For most of us, using a spectrum provided modem, even if free, is not a good longterm solution.

This issue gave me incentive to check if fiber optic was finally available in my area, and to my surprise, it has been recently supported. So instead of going through this again, because it can happen again with any other brand/model, I will just switch completely to a new service.

@James_M I contacted Netgear directly for a resolution and was told the following:

• “There is an issue on the ISP's side, and we are actively working with them to resolve it.”
• “We understand how frustrating this situation is, especially when you're caught between two providers. We truly value your loyalty to Netgear and want to assure you that we're actively working with Spectrum to identify and resolve the issue.”

I really appreciate your help and engagement in this thread. That said, it’s concerning that Spectrum and Netgear haven’t clearly aligned or taken ownership of this issue, regardless of which side pushed the firmware. The reality is that many customers are being impacted through no fault of their own. Can you share any more insight into whether Spectrum’s team is actively working with Netgear on a resolution?

It also raises questions about why Spectrum continues to list the Netgear CM3000 as an authorized retail modem while these issues remain unresolved (https://www.spectrum.net/support/internet/compliant-modems-spectrum-network). Customers may want to reconsider purchasing this modem until it is confirmed to work properly on Spectrum’s network.

At this point, I have a technician scheduled tomorrow morning to address a poor signal, which appears to be caused by the firmware update, and they'll likely find that my cable is fine. After that, I’ll likely need to lease a temporary modem from Spectrum, activate it, and then monitor updates online until the CM3000 firmware is reverted or corrected so I can reactivate it. This is a frustrating and time-consuming process for customers.

What would help most right now is a clear statement from Spectrum and Netgear on whether this issue is being actively worked on together, and when customers can realistically expect a fix.

This is why you always use the free Spectrum provided modem. No reason to buy your own and just burning money, literally. High split is not even supported or enabled with customer owned modems by Spectrum.