# New sensor won't accept any calibration - "Unknown code: 12"
**URL:** https://forum.fudiabetes.org/t/new-sensor-wont-accept-any-calibration-unknown-code-12/8669
**Category:** Type 1 & LADA
**Tags:** xdrip, cgm, dexcom
**Created:** [November 14, 2019, 2:12pm UTC](https://forum.fudiabetes.org/t/new-sensor-wont-accept-any-calibration-unknown-code-12/8669 "2019-11-14T14:12:06Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@bwschulz](https://forum.fudiabetes.org/u/bwschulz)
#### Post date: [November 14, 2019, 2:12pm UTC](https://forum.fudiabetes.org/t/new-sensor-wont-accept-any-calibration-unknown-code-12/8669/1 "2019-11-14T14:12:06Z")
I started a new G6 sensor on Xdrip+ yesterday and it’s been a PITA. First off it gives me the error “G5 sensor start failed” (remember, it’s a G6 sensor). But it still does the warm-up period and starts working. However, it rejects every single calibration, even maddeningly after it asks for one. The error is always the same:
Calibration Rejected:
Unknown code: 12
The first two calibrations were off by quite a bit - 16% and 32%, so I thought it might be out of too far off to believe. But the third fingerstick was exactly the same as the CGM so that isn’t it. Double calibration and repeated calibrations all rejected. Restarting the sensor gives the exact same results. Anyone have any ideas about what’s going on with this thing and how I might be able to fix it?
---
### Author:  [@docslotnick](https://forum.fudiabetes.org/u/docslotnick)
#### Post date: [November 14, 2019, 2:36pm UTC](https://forum.fudiabetes.org/t/new-sensor-wont-accept-any-calibration-unknown-code-12/8669/2 "2019-11-14T14:36:39Z")
@bwschulz The G6 shouldn’t be asking for calibrations unless you didn’t put the four digit sensor code in. Maybe you didn’t check “I am using G6” in settings\>G5/G6 Debug Settings"?
---
### Author:  [@bwschulz](https://forum.fudiabetes.org/u/bwschulz)
#### Post date: [November 14, 2019, 3:02pm UTC](https://forum.fudiabetes.org/t/new-sensor-wont-accept-any-calibration-unknown-code-12/8669/3 "2019-11-14T15:02:29Z")
It might have asked for a calibration because I entered a double calibration in the attempt to get it to accept something (which may have bumped it out of G6 and into G5 mode), but that G6 tickbox is checked. I’ve been using this setup (G6 with Xdrip+) for a long time now and have never had anything like this. I’ve had some sensors that had issues on startup but they eventually settled down or restarted fine. This one is just goofy. I restarted it again this morning and it says “Please wait while sensor warms up!” while at the same time still merrily displaying BG readings. I’ve never had that happen either.
---
### Author:  [@Jason99](https://forum.fudiabetes.org/u/Jason99)
#### Post date: [November 14, 2019, 3:05pm UTC](https://forum.fudiabetes.org/t/new-sensor-wont-accept-any-calibration-unknown-code-12/8669/4 "2019-11-14T15:05:39Z")
Which transmitter are you using? The new 8g and 8H transmitters don’t allow third party apps to connect to them
---
### Author:  [@Thomas](https://forum.fudiabetes.org/u/Thomas)
#### Post date: [November 14, 2019, 3:10pm UTC](https://forum.fudiabetes.org/t/new-sensor-wont-accept-any-calibration-unknown-code-12/8669/5 "2019-11-14T15:10:28Z")
The 8Hxxxx sees the light of day…
lol
---
### Author:  [@Jason99](https://forum.fudiabetes.org/u/Jason99)
#### Post date: [November 14, 2019, 3:12pm UTC](https://forum.fudiabetes.org/t/new-sensor-wont-accept-any-calibration-unknown-code-12/8669/6 "2019-11-14T15:12:42Z")
I got a two pack last month
---
### Author:  [@bwschulz](https://forum.fudiabetes.org/u/bwschulz)
#### Post date: [November 14, 2019, 3:17pm UTC](https://forum.fudiabetes.org/t/new-sensor-wont-accept-any-calibration-unknown-code-12/8669/7 "2019-11-14T15:17:35Z")
I don’t know the specific model, but this transmitter has been working fine for many other sensors.
---
### Author:  [@Thomas](https://forum.fudiabetes.org/u/Thomas)
#### Post date: [November 14, 2019, 4:22pm UTC](https://forum.fudiabetes.org/t/new-sensor-wont-accept-any-calibration-unknown-code-12/8669/8 "2019-11-14T16:22:31Z")
> [@bwschulz](#):
>
> I don’t know the specific model …
The first two characters of the Transmitter serial number.
With the various transmitters out there it helps to know which one is being discussed.
Sometimes it is relevant and sometimes not.
---
### Author:  [@bwschulz](https://forum.fudiabetes.org/u/bwschulz)
#### Post date: [November 14, 2019, 5:01pm UTC](https://forum.fudiabetes.org/t/new-sensor-wont-accept-any-calibration-unknown-code-12/8669/9 "2019-11-14T17:01:11Z")
Thanks- it’s an 81XXXX.
What are Xdrip+ users going to do/doing when they get those new 8g or 8H transmitters that don’t work? Is that forcing them back to the crappy Dexcom app, or is there any workaround?
---
### Author:  [@jbowler](https://forum.fudiabetes.org/u/jbowler)
#### Post date: [November 17, 2019, 5:47am UTC](https://forum.fudiabetes.org/t/new-sensor-wont-accept-any-calibration-unknown-code-12/8669/10 "2019-11-17T05:47:02Z")
> [@bwschulz](#):
>
> What are Xdrip+ users going to do/doing when they get those new 8g or 8H transmitters that don’t work?
The various transmitters were described in a posting [here](https://seemycgm.com/2019/08/01/restarting-dexcom-g6-sensors-updated/), but that seems inaccurate given, with regard to the 8G and xDrip+:
> [@Dexcom G6 “Firefly” 8G Transmitter and Unsupported Android Phones](https://forum.fudiabetes.org/t/dexcom-g6-firefly-8g-transmitter-and-unsupported-android-phones/8564/4):
>
> 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+.
Anyway I will know in the coming month because my 81 transmitter has 88.6 days on the clock and the only replacement I have is an 8G (unless Walmart supplies me with an earlier transmitter in the next few days, this is entirely possible.)