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NOTICE: CM3000 cable modem v6.01.04 Firmware Released
Getting some reports that this version of FW is being seen on CM3000 series modems from CC/XF ISP. Not sure if other ISPs will be seeing this. Maybe at some point.
This seems to follow up on last years v.03 FW that was a bust and was pulled from use by the ISP and NG which resulted in users modems being downgraded back to prior v5 working FW.
Anyone seeing this, please give feedback on your experiences seen with this version loaded on the CM3000 modem.
Hopefully good results.
20 Replies
Sometime around 11/18/2025 Cox Communications upgraded my CM3000 to the v6.01.04 firmware. It has been unusable ever since. When connected up to a router, the internet connection is never completed. I've tried both an MR80 mesh router and an older R7000P. Luckily, I still have my CM1200 modem, which works just fine with either router.
This CM3000 is still under warranty, since I purchased it in August of this year (2025). Netgear support seems to be giving me the runaround: having me reboot, reset, reset, etc. They've never admitted to an issue with this modem.
Any suggestions as to how I can better get their attention and resolve this?
Had the CM3000 been fully associated with the ISP and then after that after connecting a router to the CM3000 modem, power OFF The modem for 30 seconds then back ON, then give about 1 minute power ON the external wifi router?
Yes, the modem worked just fine from 08/18/2025 to 11/16/2025. And I have run through the reboot/reset process several times with the Cox representative on the phone with me. I also have an outstanding case with Netgear, and they just keep telling me to do the same thing.
As an aside, I'm retired after 40+ years working in the IT industry, so I'm pretty familiar with how this works.
Power OFF and back ON differs from reboot and reset.
You will need to put the CM3000 series back online and get it associated with the ISP. Have one ethernet connected PC connected to the modem. Not a router and see if you can get internet access.
Then capture the CM3000s cable connection and event logs from the modem and post here.
So far your the only one posting about this version of FW since NG released it.
I have performed the modem reset, and connected the modem LAN port directly to a computer via an ethernet cable. The DHCP server at Cox gives me an IP address, but I cannot connect to the internet.
I have already sent Netgear the diagnostics they requested, as a result of being able to connect to the modem at 192.168.100.1
After 5 weeks of absolutely frustrating up and down Internet, I'm done with the CM3000 on Cox. It is not compatible and resetting it 10 times a day is crazy. Cox will NOT downgrade the FW and I made that request at the highest level with a tech that knew it can not be done. So NG says your ISP controls firmware and the ISP says you need to get firmware from the modem manufacturer. In other words, Cox upgraded my CM3000 to V6.01.04 upon 1st provisioning and crippled it... until perhaps they get around to fixing problems and pushing out a new update to eliminate the critical time sync, dynamic range window warning, TCS partial service warning, and many more problems. There have also been dozens of attempts to download new firmware and they all fail for being incompatible or corrupt and that puts the modem into an unstable state. Cox says they are not pushing FW updates... so then who is? Not likely NG, which Cox suggested it was. That was a waste of $280 to test this out but note that Cox still has the CM3000 on their list of certified DOCSIS 3.1 modems.
I'll try another brand that Cox claims does not have user reports like the CM3000 (switching to the S34).
What FW version is on the Cm3000 currently?
Please post a copy and paste of the modems connection status and event log page.
What is the brand and model of the host wifi router connected to the modem?
After 5 weeks of absolutely frustrating up and down Internet, I'm done with the CM3000 on Cox. It is not compatible and resetting it 10 times a day is crazy. Cox will NOT downgrade the FW and I made that request at the highest level with a tech that knew it can not be done. So NG says your ISP controls firmware and the ISP says you need to get firmware from the modem manufacturer. In other words, Cox upgraded my CM3000 to V6.01.04 upon 1st provisioning and crippled it... until perhaps they get around to fixing problems and pushing out a new update to eliminate the critical time sync, dynamic range window warning, TCS partial service warning, and many more problems. There have also been dozens of attempts to download new firmware and they all fail for being incompatible or corrupt and that puts the modem into an unstable state. Cox says they are not pushing FW updates... so then who is? Not likely NG, which Cox suggested it was. That was a waste of $280 to test this out but note that Cox still has the CM3000 on their list of certified DOCSIS 3.1 modems.
I'll try another brand that Cox claims does not have user reports like the CM3000 (switching to the S34).
Status:
Cable Diagnostic Status: Poor Action:
[Partial Service]
If the Partial Service mode does not go away within a few hours (Click the Refresh button after each step):
1) Make sure the coaxial cable is tightly connected.
2) Remove any unnecessary splitters.
3) Replace any required ones.
4) Contact your service provider for troubleshooting help.CM Status: Downstream Status: Upstream Status: Refresh Save Cable Diagnostic Info Advanced Information Frequency Start Value This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect. Starting Frequency Startup Procedure Procedure Status Comment Acquire Downstream Channel 747000000 Hz Locked Connectivity State OK Operational Boot State OK Operational Security Enabled BPI+ IP Provisioning Mode Honor MDD IPv4 only Downstream Bonded Channels Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables 1 Locked QAM256 5 747000000 Hz 6.6 dBmV 42.8 dB 0 0 2 Locked QAM256 1 723000000 Hz 5.7 dBmV 42.6 dB 0 0 3 Locked QAM256 2 729000000 Hz 5.6 dBmV 42.5 dB 0 0 4 Locked QAM256 3 735000000 Hz 5.9 dBmV 42.6 dB 0 0 5 Locked QAM256 4 741000000 Hz 6.2 dBmV 42.7 dB 0 0 6 Locked QAM256 6 753000000 Hz 7.0 dBmV 42.8 dB 0 0 7 Locked QAM256 7 759000000 Hz 7.1 dBmV 42.9 dB 0 0 8 Locked QAM256 8 765000000 Hz 7.2 dBmV 42.9 dB 0 0 9 Locked QAM256 25 117000000 Hz 0.9 dBmV 39.8 dB 0 0 10 Locked QAM256 26 123000000 Hz 1.2 dBmV 40.1 dB 2 0 11 Locked QAM256 27 129000000 Hz 1.3 dBmV 40.4 dB 1 0 12 Locked QAM256 28 135000000 Hz 1.2 dBmV 40.6 dB 3 0 13 Locked QAM256 29 141000000 Hz 1.0 dBmV 40.7 dB 3 0 14 Locked QAM256 30 147000000 Hz 0.9 dBmV 40.7 dB 0 0 15 Locked QAM256 31 153000000 Hz 1.4 dBmV 40.8 dB 0 0 16 Locked QAM256 32 159000000 Hz 1.7 dBmV 41.1 dB 0 0 17 Locked QAM256 33 165000000 Hz 1.8 dBmV 41.1 dB 0 0 18 Locked QAM256 34 171000000 Hz 1.8 dBmV 41.1 dB 0 0 19 Locked QAM256 35 177000000 Hz 1.7 dBmV 41.1 dB 0 0 20 Locked QAM256 36 183000000 Hz 1.9 dBmV 41.1 dB 0 0 21 Locked QAM256 37 189000000 Hz 2.1 dBmV 41.3 dB 0 0 22 Locked QAM256 38 195000000 Hz 2.3 dBmV 41.4 dB 0 0 23 Locked QAM256 39 201000000 Hz 2.6 dBmV 41.4 dB 0 0 24 Locked QAM256 40 207000000 Hz 2.8 dBmV 41.5 dB 0 0 25 Locked QAM256 41 213000000 Hz 2.9 dBmV 41.6 dB 0 0 26 Locked QAM256 42 219000000 Hz 2.9 dBmV 41.6 dB 0 0 27 Locked QAM256 43 225000000 Hz 2.9 dBmV 41.6 dB 0 0 28 Locked QAM256 44 231000000 Hz 2.8 dBmV 41.6 dB 0 0 29 Locked QAM256 45 237000000 Hz 2.6 dBmV 41.6 dB 0 0 30 Locked QAM256 46 243000000 Hz 2.4 dBmV 41.5 dB 0 0 31 Locked QAM256 47 249000000 Hz 2.3 dBmV 41.4 dB 0 0 32 Locked QAM256 48 255000000 Hz 2.3 dBmV 41.4 dB 0 0 Upstream Bonded Channels (Partial Service) Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power 1 Locked ATDMA 2 5120 Ksym/sec 24000000 Hz 43.5 dBmV 2 Locked ATDMA 1 5120 Ksym/sec 17600000 Hz 43.5 dBmV 3 Locked ATDMA 3 5120 Ksym/sec 30400000 Hz 43.0 dBmV 4 Locked ATDMA 4 5120 Ksym/sec 36800000 Hz 43.5 dBmV 5 Not Locked Unknown 0 0 0 0.0 dBmV 6 Not Locked Unknown 0 0 0 0.0 dBmV 7 Not Locked Unknown 0 0 0 0.0 dBmV 8 Not Locked Unknown 0 0 0 0.0 dBmV Downstream OFDM Channels Channel Lock Status Profile ID Channel ID Frequency Power SNR / MER Active Subcarrier
Number RangeUnerrored
CodewordsCorrectable
CodewordsUncorrectable
Codewords1 Locked 0 ,1 ,2 ,3 159 300000000 Hz 2.78 dBmV 42.0 dB 296 ~ 7895 465476710 416880508 0 2 Not Locked 0 0 0 Hz 0 dBmV 0 dB 0 ~ 4095 0 0 0 Upstream OFDMA Channels Channel Lock Status Modulation / Profile ID Channel ID Frequency Power 1 Not Locked 9 ,13 6 36800000 Hz 36.5 dBmV 2 Not Locked 0 0 0 Hz 0 dBmV Extended Upstream Transmit Power Current System Time:Wed Aug 12 14:34:37 2026 System Up Time:02:04:22 Event Log:
Time Priority Description Wed Aug 12 13:20:39 2026 (Warning (5)) TCS Partial Service;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Wed Aug 12 12:33:52 2026 (Error (4)) DBC-ACK not received;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Wed Aug 12 12:33:49 2026 (Warning (5)) TCS Partial Service;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Wed Aug 12 12:32:50 2026 (Critical (3)) SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Wed Aug 12 12:32:10 2026 (Notice (6)) US profile assignment change. US Chan ID: 6; Previous Profile: 13; New Profile: 9 13.;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Wed Aug 12 12:31:10 2026 (Warning (5)) Dynamic Range Window violation Wed Aug 12 12:31:10 2026 (Warning (5)) RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Wed Aug 12 12:31:03 2026 (Notice (6)) DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Wed Aug 12 12:30:58 2026 (Notice (6)) TLV-11 - unrecognized OID;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Time Not Established (Warning (5)) DHCP WARNING - Non-critical field invalid in response ;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Time Not Established (Notice (6)) Honoring MDD; IP provisioning mode = IPv4 Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; Wed Aug 12 12:29:46 2026 (Critical (3)) Resetting the cable modem due to docsDevResetNow Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; Wed Aug 12 12:28:06 2026 (Critical (3)) Resetting the cable modem due to docsDevResetNow Wed Aug 12 11:59:09 2026 (Critical (3)) SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; Wed Aug 12 10:30:51 2026 (Critical (3)) SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; Tue Aug 11 17:35:05 2026 (Critical (3)) SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; Tue Aug 11 15:01:22 2026 (Critical (3)) SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; Sun Aug 09 21:24:04 2026 (Critical (3)) SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; Sat Aug 08 19:54:40 2026 (Critical (3)) SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; Sat Aug 08 06:40:18 2026 (Critical (3)) No Ranging Response received - T3 time-out;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Sat Aug 08 06:40:13 2026 (Critical (3)) SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; Fri Aug 07 10:05:00 2026 (Critical (3)) SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; Fri Aug 07 08:39:19 2026 (Critical (3)) No Ranging Response received - T3 time-out;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Fri Aug 07 08:39:17 2026 (Critical (3)) No Ranging Response received - T3 time-out;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; Thu Aug 06 12:59:10 2026 (Critical (3)) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Thu Aug 06 12:55:38 2026 (Critical (3)) SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; Thu Jul 23 06:40:36 2026 (Critical (3)) SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=f8:a7:3a:f0:e5:d5;CM-QOS=1.1;CM-VER=3.1; Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:94:01:ab:79:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; And my apology, but the firmware version is:
Cable Information Hardware Version 1.01 Cable Firmware Version V6.01.04 Ok, Looking at your power levels, seem a bit all over the place on the upper side across channels. A couple channels are on or near the max for the upper limit:
https://kb.netgear.com/24311/Power-level-guidelines-for-a-NETGEAR-cable-modem-router
You might check into a -3dbm or -6dbm coax line attenuator to install.
Any Criticals, Errors or Warnings seen in the event logs needs to be reviewed and resolved by the ISP. Indicates a signal issue on the ISP line up to the modem.
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.
Start with removing any amplifiers, signal attenuators, or splitters from the coax.
From there check the line for kinks, damage, moisture in the line.
Check the connectors for improperly made ends, foil touching the copper coax line, loose connections, bad/old/cheap connectors, or corroded connections. Replace them if you do.
Be sure to power OFF the modem for 1 minute then back ON.
https://www.duckware.com/tech/solving-intermittent-cable-modem-issues.html
https://highspeed.tips/docsis-events/
I'll see if I can get some review from NG on this as well.
Thanks- I appreciate the information. This is a new construction house with all new coax including the run from the demarcation box outside the house to the Cox pedestal 30 feet away in the front yard. Terminations look good but I cannot inspect the run the guys came by and trenched in the yard a week ago (but there was no change in reliability from that work). I made sure there is only 1 coax connected at the demarc and it runs straight to the modem with no splitters, no amplifiers or even connectors. And that run from the demarc to the modem is about 20 feet in the crawl space (looks fine).
I agree on power levels and I typically try to get +2 dBmV across the channels and hope for 44-ish dB SNR. This configuration is way off but still in the window for the CM3000. I had Cox re-provision the modem this morning and so far it's holding the Internet but has lost the upstream OFDM lock as the modem status shows.
With Cox when you bring your own modem they simply look the other way and say you're on your own for tech support. Therefore they will not assist in analyzing the CM3000 error log even though it points to them for problems. They only care about getting a signal on the cable at the modem-- beyond that, they don't care and won't lift a finger to help. I do have some testers (Klein) to ring out the coax runs but I do not have a high frequency signal source or a scope to get a look at the frequency response.
I've read about far too many issues with the CM3000 on Cox and that is why I plan to decommission it when the Arris arrives.
The CM3000 is connected directly to a TP-Link Omada Gateway/Router model number ER707-M2 into the 2.5G port. It then goes into a TP-Link Omada POE Switch model number SSG2218P. All TP-Link hardware is managed by an OC220 Controller and all firmware is updated by TP-Link to the latest as of 12-August-2026.
