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...