The dread G6 session-restart block is here

[Dark epic film-teaser voice] And so it begins. In a world…

I went to do my first sensor-restart yesterday after getting a new transmitter last week, and all the ill-omens and dark murmurings you’ve heard are true. It blocks you from doing the forget-code/restore-code restart method. About half an hour into the warm-up it threw up a No Restart Allowed message. I did try the more elaborate method where you have to “forget this device” in the Bluetooth preferences (IOS) but that just caused me a lot of trouble, either b/c the instructions I had were inadequate or I did something wrong (pretty sure it was the former) and I finally broke down and put in a new sensor.

So dang. I’m not concerned about the expense so much as the fact that I’ve been having difficulty finding trouble-free insertion spots and I hate having to deal with the the initial 24-hour wobbles when I’ve got a good pain-free location and stable sensor going.

Also: what about pre-soaking, is that going to be blocked too? Because supposedly the new algorithm is validating on the basis of “insertion trauma,” i.e., if your data looks too smooth it assumes you’re restarting an existing sensor. And the whole point of pre-soak is that you initiate the session after the sensor has been in there long enough to stabilize. So that could be a really annoying downside. If an actual new sensor gets rejected on this basis, will Dexcom replace it? Do they even know people are doing this in order to get better first-day results?

And yeah, xDrip, but I have the latest version and couldn’t seem to get it to connect when I tried it at the end of my last transmitter.

Has anyone found a good hack for this?


What’s the serial number for your transmitter? The ones I received in June had the 81xxx serial number. All the previous ones started with 80. The first worked fine using the restart protocol your mentioned, but I had planned to start the second one today. May change those plans if we learn more about when the update was implemented.

Anyone know if Spike for iOS is available again? If so, anyone know how to install it? I reset the clock on an 80xxx series transmitter earlier this year without issue.

Not likely, but can Dexcom update the transmitter firmware remotely via the G6 app or Clarity? The reason I ask is because Dexcom knows when you start using a transmitter. I placed a tech support call earlier this year when I was using the transmitter I reset with Spike. They asked for the transmitter number and based on that told me the exact date I first started using it, told me it was expired, and refused support. Communication between Dexcom and the transmitter must exist.

If you’re using the new transmitter that starts with 8G, restarts are not allowed and they are not compatible with any 3rd party applications.

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I don’t use a smartphone to manage my Dexcom hardware as 1) I started exclusively using the supplied Dexcom receiver when Medicare patients were not allowed to use smartphones. 2) Tried installing and using xDrip+ on my HTC U12+ Android smartphones and was never successfully able to make it work.

My Dexcom receiver shows Transmitter Serial Number and Activation date in the Transmitter settings info. About 1 year ago I did have a transmitter early failure and when I called tech support, they had a record of all transmitters they had sent out as well as activation dates. The only thing they asked me to confirm was that the transmitter on my body was the one shown in the receiver and a date found on the transmitter box.

Based on this, my belief is that whenever data is uploaded to Clarity, the transmitter serial number and activation date is also being uploaded even though that does not show in the Clarity settings that can be viewed by a home user.

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Well poop. Mine’s an 8G, yup.


@Dave44 posted a link breaking down what the 8g is all about. I can’t find it, hopefully he can post it again. Honestly, this is no surprise that Dexcom is protecting their product and IP from 3rd party hackers.

Yeah, can’t blame them, it’s just an annoyance. OTOH they’re supposed to be extending the statutory sensor limit to 14 days soon, so that’s something to look forward to.


Have you used this method posted by Katie DiSimone at SeeMyCGM?

The sure way around “no restarts”: Bluetooth Unpaired method

The only way for sure around this trauma check that I have found on both new and old transmitters alike is to use the old Option 2 method from my original post. Let’s call it the “Bluetooth Unpaired” method from now on. This method will also let you recover if you’ve already gotten a “no restarts” message on an old or new sensor. The super short description of that version is: do a restart with your transmitter unpaired the whole time.

The slightly more detailed procedure for the “Bluetooth Unpaired” method:

  1. Wait for new BG to come in and then wait about one minute. Doesn’t have to be exactly one minute…just enough of a little pause to make sure the transmitter is done talking to the app. If you session already expired, just start with step 2…no big deal.

  2. Forget/delete Dexcom from Bluetooth list in phone’s settings. iPhone users, tap the little “i” next to every Dexcom ID in your bluetooth list and forget the pairing(s).

  3. “Stop Sensor”, “New Sensor”, enter code, “Start Sensor”

  4. Wait 2 hours and 5 min minimum for the warmup to finish. Do not accept any pairing requests during that time. You’ll probably see “transmitter not found” display on the Dexcom app during this time. You can use your phone as normal during this time, but I advise turning off Dexcom app in the Notifications section of your phone settings so that you don’t keep getting pinged every 5 minutes.

  5. After the warmup wait, open Dexcom app and wait for pairing request.

  6. Accept pairing request. You may see “signal loss” message for up to 5 min after this setup.

  7. BGs and fresh 10-day session should appear after that signal loss clears in five minutes.


Hopefully they implement that soon for people like you that have a limited amount of sweet spots to choose from on your body.

This doesn’t work with the new transmitters starting with serial number 8G. Dexcom just started to rollout these new Firefly transmitters within the last month.

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You rock @Dave44


I don’t have direct experience with the G6. Katie DiSimone wrote:

The only way for sure around this trauma check that I have found on both new [G6 Firefly with 8Gxxxx fromat serial number and the 6+ transmitter with 22xxxx serial number per cited article] and old transmitters alike is to use the old Option 2 method from my original post.

Is Katie wrong about this or is 8-1-19 publication now out of date? The only reason I question is because I have found her a highly dependable source of information.


I have know idea who she is, I can’t speak to whether she’s right or wrong. The article Dave linked to and the subreddit about this new transmitter state it cannot be restarted or cannot be restarted without causing problems with the sensor.

@Terry4 Drbb tried that method this morning and had trouble with it and gave up. Who knows at this point.

Katie wrote LoopDocs and LoopTips, the instructions for building Loop. Did you read the info found at @Dave44 posted a link to the same site and it does not say that it cannot be restarted without causing sensor problems.

Not sure about the veracity of a subreddit thread.

If @DrBB tried this method and failed, I would encourage him to try it again and make sure he has followed every step. Things are changing quickly in this context but Katie’s lack of follow-up regarding the failure of this method to work makes me wonder if he missed some point in the process.

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My bad, the sensor problem is with the 15 minute method. When I get back home and replace my transmitter with these new ones I’ll give it a try. I typically don’t restart my sensors unless I’m really not in the mood to change an expiring sensor.

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These kind of comments do not encourage me to interact. It puts a chill on things, don’t you think?

Sorry for the meta-distraction @DrBB. I will try to be better.


I read a Dexcom press release sometime in past 9 months where the CEO addressed some “issues” with the FDA wrt transmitter restarts.

He said their engineers were aware of all the hacks and were continuously changing Tx protocols to thwart restarts (they can read forums like this one as easily as anyone).


Yup. Most people have seemed to forget that hacking durable medical equipment is a federal crime. I’m sure the days are coming where these folks are going to be prosecuted.