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Arris S34 is finally working for next-gen fast upload speeds (with a lot of effort)

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For the past couple months I have been trying to get the Arris S34 to support the next-gen fast upload speeds, and with some help from the reddit support reps, I finally had success tonight! I have the 800/100 plan, but my upload speed had been limited to about 23.9 (20 + 120% overprovision). Here is the old/slow speed test and the new/fast speed test result. Woohoo!

I am posting some troubleshooting steps in the hope that other S34 owners can point support reps to this thread and get next-gen speeds. Since I have the 800/100 plan, I'll use that example below, but please substitute your actual plan speeds.

  1. Eligibility: Make sure your address is eligible for the next-gen speeds. In my case, xfinity did some upgrades in my neighborhood and the internet was down periodically for a whole day, and then a few months later, I got an email indicating I was eligible.

  2. Hardware: Sometimes support reps think the Arris S34 is not next-gen compatible because they are using an old copy of the approved hardware list. Please point them to the 8/14 next-gen list here.

  3. Billing code: Your billing code should reflect the 800/100 speeds. This is something the support rep can confirm and fix, if necessary. On the xfinity account website, I can click "Internet" under "Your services" at the top left corner and see something like "Download speed: up to 800 Mbps, Upload speed: up to 100 Mbps", and I think this should be matched to the billing code, but I am not sure. In any case, if the website says your upload speed is 20, this probably needs fixed. Note that my billing code appeared correct (800/100), and I was still not getting the 100 upload speed.

  4. Boot file, special code: It seems I was not getting the correct boot file when my modem restarted, but a "special code" can help force the right boot file to be sent. Here is a quote from the support rep: "I have a code that I can add to try and force the correct bootfile to come through. We add that in our billing system but it doesn't change any details of your plan or pricing. This will cause the modem to provision again and reset. This should get the faster speed coming through when you are back online." So, ask them to add that code!

  5. Provisioning signal, disconnect personal router during reboot: I am not convinced this is necessary, but the rep suggested it, and I did it. Here is a quote from the rep: "If you have a separate router. I ask that you please unplug the power to it while I take these steps. The router can intercept the provisioning signal and the modem ends up with it. At the end of my process the modem will reset. When it comes back online, you could plug the router back in."

Since I tried both steps #4 and #5 together in a single reboot event, I am not sure if the special code was the fix or if disconnecting my router during the reboot was the fix (or if both were necessary!). If you have time to experiment with the rep, maybe try these steps separately.

As an aside, why the S34 vs. other alternatives? I've been using SURFboard modems for 20+ years (since the trusty SB4200) with much success, and the S34 is small, white, and cute... and it looks great on my desk. The old Arris office is about 5 min from my home, and the S34 actually shipped from their warehouse right here in town. Maybe I'm still nostalgic for that day I first upgraded from dial-up with the help of one of these SURFboards. And they haven't updated the web UI in 20 years, so nothing new to learn there, haha!

In any case, thanks to the (many) reps for attempting, and finally succeeding, in getting this to work!

Good luck to the rest of y'all...

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Guess I must have been lucky. Plugged in my new modem and got 1500 down and 300 up right out the gate. Didn’t need to do anything. Glad it’s working for you though and appreciate you adding the guild to help people in the future

That's awesome! Hopefully they are starting to get their act together (in some areas or for some plans).

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One last note: If you want to confirm everything is working OK from a hardware perspective, if you log in to the modem web UI, I believe you should see at least one (maybe two) "OFDM PLC" downstream channels and one "OFDMA" upstream channel (in addition to all the other QAM channels), and they should be in "Locked" status. Example from my modem is here.

And the Event Log tab in the UI doesn't work in Chrome... gotta use Edge, lol.

So I figured out why the event log disappears for many. Even across browsers!

The event log itself is fetched by a JS file called eventlog.js. There’s a filter rule against this in the EasyPrivacy list used by uBlock Origin. If you manually override this, then the event log will function again.

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If there is a Comcast agent who is willing to try and get mine to work again please let me know. My plan is for 2000/400 but I am only getting 1200/40. I have had no luck with service reps yet.

To get their attention, you'd probably need to start a new post and then send modmail.

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I’ve been receiving T3 errors and had a tech out yesterday. Tech said he didn’t find anything but tightened the connections (everything runs underground here) and the SNR improved drastically. He insisted at first that no consumer modem was capable of 350 mbps upload speeds and I told him that is what I was getting. He still didn’t fix these ongoing issues. He mentioned random disconnects at this point could be due to ingress from someone else’s modem.

It just goes to show that even the techs are clueless these days.

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This is very interesting. I am going to try a reboot of my Arris S34 modem first. Then I will contact Xfinity for the boot file and more troubleshooting if the rebooting of the modem does not work. I have been waiting for years to get 2gbps down/400mbps up and it was all waiting on xfinity to create the boot file for support. Instead they kept pushing newer hardware so that I would spend more $$$$ when I knew my modem supported the speeds ALREADY. I'll report back with what I find and the results of troubleshooting.

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Current next gen list (9/18/2024). Essentially same as the 8/14 list posted above.

Wonder when the S34 will be considered a recommended device. It's compatible with the next-gen speed devices, but not listed as a recommended/optimized device.