Dexcom G6 “Firefly” 8G Transmitter and Unsupported Android Phones

I’ve read that the new 8G “Firefly” transmitters for the Dexcom G6 do not function with 3rd party apps such as X-drip.

Does anyone have first hand experience with this? What about the “Custom Built Dexcom App” that bypasses the check for phone model, but otherwise acts like the standard Dexcom app? Are there other “second receiver” options people use with the Tslim/G6 combo?

My context…
I’m currently using the Dexcom G4 (since 2012) and Medtronic 523 (since 2013). I’m thinking about switching to the Tslim and Dexcom G6, but I’m concerned about receiver options.

I like to be able to see my data on my desk, or on an arm band when I’m exercising or the pump is inaccessible under ski gear. Unfortunately, Dexcom doesn’t support my phone or the one I might want next (Moto X4, Pixel 3a).


I’m pretty much in the same boat. I am starting to order G6, while I finish up G4s. G4 transmitter out of warranty, but still may work for a few more months. I also will consider t-slim when 523 warranty ends early next year.

There have been some that successfully restart firefly 8G, but it does get trickier, and sometimes only a few more days of use. Once I have pump that changes insulin flow based on CGM (basal-IQ), I may be less likely to extend if G6 is not smooth transition.

I was able to get 2 of the older G6 transmitters at lower cost from Costco, and may try battery replacements on them. Will miss using G4 transmitter for about a year for each one over the past several years.

I use xDrip on cheap phone without phone service, so basically just like a receiver. Have tried it for both G4 and G6, so getting used to it. I have a fitbit ionic and custom app to see xDrip on it (called Glance). But that means carrying another device for xDrip.


I think the Basal-IQ on the X2 with the G6 is good enough to change your phone preference.

We have been using the Basal-IQ for 13 months now.

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That’s not what I’ve heard. There have been some problems with sensor restart to defeat the 10 day lock, but that has been solved in the latest nightly releases, but the initial start has not been a problem. The Moto and Pixel should work fine with xDrip+.


That’s really great to know - I was having some trouble differentiating who was talking about just using the app to collect data vs using it to restart the sensor.

I’m not toooo worried about re-starting since I usually only get ~12-13 days of data reliable enough for decision making anyway. I figure Basal IQ is probably worth losing a couple days on each sensor.

(Also, I’m sorry it’s taken me so long to reply - I do appreciate the feedback!)

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I am pretty excited about Basal IQ! I held off for a long time b/c I was afraid it would induce high BGs, but from the reviews I’ve read almost no one has problems with that. I’m actually planning to submit my insurance paperwork tomorrow. :smile:

Hopefully Control IQ is also better than my skeptical expectations. The NEJM study supplementals look like Control IQ might slightly raise A1Cs for people with starting A1Cs below 6. There were so few people starting with low A1Cs, though, and no data on how much time they were spending low to start.

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It’s good to hear someone else is in the same boat. My Endo seems to think I’m the last hold-out for both the 523 and the G4.

Thanks for mentioning Glance - I didn’t realize it was even possible to put custom apps on a FitBit! Any chance it’s possible to silence alarms through Glance without waking up the phone? That would be useful for exercise…

I’ve been waiting for direct-to-watch data collection, but it may be worth it to consider watches once I get rid of the G4 receiver.

(Sorry for the super-late reply!)

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We love Basal IQ, it allows us to be much more aggressive than before with little worry if we miss a little. Of course, if we miss a lot Basal IQ can only do so much, but our comfort with just before bed corrections has gone through the roof. Try it, I am sure you will find a good way to use it. We are still skeptical about Control IQ, but hope they can both exist on the same pump and be switched between. Then we can try without having to worry about reverting if we just want to stick with Basal IQ.

I saw someone mention that an interruption in Basal delivery will also cancel any undelivered square-wave bolus… I can’t wait to take advantage of that feature for “sticky” highs - especially over night!

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Actually its a watchface, sorry for saying it is app.

Details here.

And yes, there are options for alerts. Mine is set up to get data from xDrip.

@Mary55 If you’re waiting for direct to watch data collection, that boat sailed long ago. I have been using my watch to collect data sans phone for almost two years. And it works with G4, 5, and 6. And Libre and Libre 2, and more.

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Wait… The G4 still requires the Dexcom receiver, right? If not, I can’t believe I missed that!

I definitely need to look into this more for the G6 - I was thinking I’d have to get a watch running the full Android OS to do this.

For anyone else who may have fallen behind, I found another thread from March that was pretty illuminating:

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One more question - could anyone comment on which is the smallest of the watches that can be made to collect Dexcom data directly?

(I have smallish wrists and the size of the watches scared me off when I last looked into this.)

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@Mary55 This is a list of watches that can be made to be collectors with xDrip+:

The only watch that can be used out of the box is the Sony Smartwatch 3, but some people have had some luck with other stock Android Wear watches. Maybe they can chime in.

FWIW, the xDRIP+ dev is working on a watch pretty much dedicated to use with xDrip+. He calls it the Bluejay

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That watch looks totally cool! Wish it woud ship to the US. Says “Currently only available for delivery to the UK and EU. Shipped from the UK” . Are there plans for USA delivery?

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@bpollina I asked Jon about shipping to the US. He said it won’t happen soon because of FCC clearance, but if I knew someone in the EU who could ship one to me, that wouldn’t be a problem.

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Thanks again for all the advice!

The Bluejay watch looks fantastic but, sadly, I too am in the US. The smaller Zenwatch actually doesn’t look too terribly large, but I’m still considering just using a FitBit with data routed through the phone…

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