Bluetooth pairing systematically lost after 2nd Windows reboot.

[fvib]

Hello

I have the following issue after Windows 10 x64 1803 upgrade from 1709.

The bluetooth pairing is systematically lost after 2nd reboot. My remote device is a Samsung Galaxy S8 Android v8.0 and Samsung Exp v9.0 (G950FXXU3CRGH/G950F0XM3CRGH/G950FXXU3CRGH) with Android app working in BLE peripheral mode.

I have scanned my PC with 'Intel diagnostic tool' and updated to the latest driver version below but the issue is not fixed and bluetooth device keep continuing to disappear from device manager. (pairing still visible on the smartphone side)

Do you know why an android device could disappear from the windows pairing menu and bluetooth device manager menu ?

Version details:

DELL Latitude 7480

Intel Dual Band-AC 8265 20.70.0.5 - Intel wireless Bluettooh to latest driver version 20.70.0.4

Find also enclosed a more detailed system report.

Regards

[idata]

Hello fvib

Thank you for joining the community. I see that you are having problems with the Bluetooth devices connected to your system, allow me to help you with the inquiries. Could you access the device manager and under the view tab select the option to show hidden devices please let me know if you can find your devices under the Bluetooth section. Could you also complete a clean installation of the driver on your system? Allow me to share with you the following link for steps to complete the installation: https://downloadcenter.intel.com/product/94150/Intel-Dual-Band-Wireless-AC-8265 https://downloadcenter.intel.com/product/94150/Intel-Dual-Band-Wireless-AC-8265 Hope this help. Regards,Leonardo C.

[fvib]

Hello Leonardo

Thanks for the support. Using the 'show hidden device' view , the device is not visible anymore.

See enclosed bitmap below.

Install has been made with recommended setup. Do you have an idea on what could make the device disappear ?

I have tested with another mobile (huawei) and get the same result.

Regards

[idata]

Hello fvib

Thank you for your response.I am looking into the situation, you have motioned that you have tested a Huawei device, could you let me the model of the device and also if you have tested any other Bluetooth devices on the system? Could you also run the Intel® DSA on your system to up complete an update of the drivers? Intel® DSA download link: https://downloadcenter.intel.com/download/24345/Intel-Driver-Support-Assistant?product=128824 https://downloadcenter.intel.com/download/24345/Intel-Driver-Support-Assistant?product=128824.Best Regards,Leonardo C.

[fvib]

Dear Leonardo

Find below requested information

- Huawei reference :

HuaWEI P20 Pro CLT-L29 with Android 8.1.0 Security patch of 5 May 2018 and Build Number CLT-29 8.1.0.128(C432)

- After running Driver Support Assistant I have the result below

Best Regards

[idata]

Hi fvib,

Please try the following steps and let us know:- Perform a https://www.intel.com/content/www/us/en/support/articles/000022173/network-and-i-o/wireless-networking.html Clean Installation of Wireless Drivers. Try using the driver from your https://www.intel.com/content/www/us/en/support/topics/OEMs.html Computer Manufacturer as first option, if the issues persist after that, please try installing the driver manually following this https://www.intel.com/content/www/us/en/support/articles/000017246/network-and-i-o/wireless-networking.html link You want to unzip the file to your OS system and update the driver using the msi file.All the best,-Chris

[idata]

Hi f vib

According to the screenshot you also have an external Bluetooth USB device connected. If I remember correctly, if there is an external Bluetooth device connected this will disable the Bluetooth portion of the Intel wireless card and disconnect whatever is paired. I would recommend removing the external portion and try again.

Thanks,

[fvib]

Hello orlich

Thanks for the feedback. External Bluetooth is not plugged when Intel wireless is used, anyway I have cleaned it from device manager and made the test again without success. The point is that the Bluetooth instance is always removed after the 2nd reboot , I mean first reboot is ok and the mobile is properly detected by Windows and connection is ok. Is there something in Bluetooth behavior that can produce a bonding removal?

Regards

[idata]

Hello f vib

I have been trying to reproduce the issue you are having with the same configuration and even using a Galaxy S6/S8 phone however the device shows on the Bluetooth list even after several reboots or cold boots. The correct behavior should be to keep all paired devices listed, unless manually gets removed.

Do you have the same issue with other BT device or just those 2 that you mentioned? My feeling is that there could be a security feature from a third party software ( Like the Antivirus ) that might remove specific devices from the list base on a specific criteria. Maybe this is good to check with AV vendor.

Please let me know how it goes.

Thanks,

[fvib]

Dear Dmorlich

Thanks for the support. During your tests did you use an Android APP with a GATT server ?

I have two updates on this issue:

1/ I noticed a change between windows 10 1803 and 1709 build regarding bluetooth pairing security ie:

Previously windows 1709 only supported Passkey Pairing mode without LE Secure Connection but now with 1803 LE Secure Connection is supported with Numeric Comparison.

As I suspected something wrong with the security feature LESC, I decided to force Windows to use Passkey pairing mode without LE Secure Connection using a rooted Android smartphone and customized BLE stack parameters.

This trick fixed the issue. I can now reboot indefinitely the PC and pairing data is never lost.

A question now is what's wrong with LESC and how can we move forward to debug the issue?

2/ A second observation then is that if I plug a old BT4.0 dongle from CSR, it also fixes the issue.

Regarding the trail of the antivirus, I think it is perhaps no more relevant.

Regards

[idata]

Hi f vib,

Glad to hear you found a workaround. Let me take this to engineering and let you know.

Are you developing a new product using the Intel Bluetooth portion? Just want to make sure you will get the correct support so I can point you also to the correct support channel.

Thanks,

[fvib]

Yes a new app for Android that talk in BLE to a Windows 10 PC through an Intel bluetooth wireless chipset.