# V1.9.1 doesn't recognize airspeed sensor

**URL:** <https://discuss.px4.io/t/v1-9-1-doesnt-recognize-airspeed-sensor/11691>\
**Category:** Uncategorized\
**Created:** [June 30, 2019, 3:17pm UTC](https://discuss.px4.io/t/v1-9-1-doesnt-recognize-airspeed-sensor/11691 "2019-06-30T15:17:16Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Damiano\_Maeder](https://discuss.px4.io/user_avatar/discuss.px4.io/damiano_maeder/32/4090_2.png) [@Damiano\_Maeder](https://discuss.px4.io/u/Damiano_Maeder)\
**Post date:** [June 30, 2019, 3:17pm UTC](https://discuss.px4.io/t/v1-9-1-doesnt-recognize-airspeed-sensor/11691/1 "2019-06-30T15:17:16Z")

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Hi guys,  
I have a twin motor fixed wing drone equipped with Pixhawk 2.4.6 by mRobotics.  
I flew this drone until yesterday succesfully with the fw 1.8, today I flashed to fw 1.9.1 and suddendly, without any change on the parameters, the system doesn’t recognize the airspeed sensor anymore.  
The airspeed sensor is this one:  
[https://store.mrobotics.io/mRo-Next-Gen-MS5525-Airspeed-Sensor-NEW-p/mro-ms5525v2-mr.htm](https://store.mrobotics.io/mRo-Next-Gen-MS5525-Airspeed-Sensor-NEW-p/mro-ms5525v2-mr.htm)

It is connected to i2c bus on a splitter, on the same splitter there are:

- Pixhawk 2.4.6 by mrobotics
- compass of this GPS module: [mRo GPS u-Blox Neo-M8N BGP + Duo Mag + USB](https://store.mrobotics.io/mRo-GPS-u-Blox-Neo-M8N-HMC5983-Compass-p/mro-gps004-mr.htm)
- Rangefinder: Garmin LidarLite V3 (already setted up on 1.8 and working)

What could be the issue that makes the airspeed not visible?

Thanks for an help

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**Author:** ![rollys](https://discuss.px4.io/user_avatar/discuss.px4.io/rollys/32/2081_2.png) [@rollys](https://discuss.px4.io/u/rollys)\
**Post date:** [July 1, 2019, 12:52pm UTC](https://discuss.px4.io/t/v1-9-1-doesnt-recognize-airspeed-sensor/11691/2 "2019-07-01T12:52:02Z")

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Just to cover all the bases first:

- Check your bootloader version to make sure it uploaded px4fmu-v3\_default.px4 firmware. If it only did the v2, then it’s possible the driver was not included (1MB limit). You can [update the bootloader](https://docs.px4.io/en/advanced_config/bootloader_update.html) then it should flash the v3 version.
- Try using the Dev version.

Good luck.

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**Author:** ![Damiano\_Maeder](https://discuss.px4.io/user_avatar/discuss.px4.io/damiano_maeder/32/4090_2.png) [@Damiano\_Maeder](https://discuss.px4.io/u/Damiano_Maeder)\
**Post date:** [July 1, 2019, 1:07pm UTC](https://discuss.px4.io/t/v1-9-1-doesnt-recognize-airspeed-sensor/11691/3 "2019-07-01T13:07:47Z")

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Hi,  
thanks for your answer.  
I’m sure it uploaded the correct fw (the one you indicated) since I downloaded it from github and manually selected it to flash the board.

It seems to be a bug in the code, Dagar is working on it.

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<div class="post-metadata">

**Author:** ![rollys](https://discuss.px4.io/user_avatar/discuss.px4.io/rollys/32/2081_2.png) [@rollys](https://discuss.px4.io/u/rollys)\
**Post date:** [July 1, 2019, 1:11pm UTC](https://discuss.px4.io/t/v1-9-1-doesnt-recognize-airspeed-sensor/11691/4 "2019-07-01T13:11:20Z")

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Great, good to know. Hopefully @dagar can resolve shortly.

Good luck.