BLE OTA Not Working with ST BLE Toolbox v1.4.3 (Works with v1.4.2)

[Dhruvbusa]

Moved from STM8 forum.

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Hello ST Community,

I am experiencing an issue with BLE OTA functionality on my STM32WB-based custom board.

I have ported the OTA functionality from the official NUCLEO BLE OTA example project to my custom service and characteristic, and it has been working fine with the ST BLE Toolbox Android app v1.4.2.

However, after updating the app to v1.4.3 (March 2025), the OTA process consistently fails. No changes were made to the firmware between tests. If I downgrade the app back to v1.4.2, OTA works reliably again.

Additionally, I noticed that STM32CubeMX was recently updated to v6.14.0, whereas my firmware was originally developed using CubeMX v6.11.0. I'm trying to determine whether the problem lies in the new app version, CubeMX updates, or a combination of both.

Questions:

1. Are there any breaking changes or modifications in OTA behavior with ST BLE Toolbox v1.4.3?

2. Has the OTA protocol or image transfer mechanism changed (e.g., chunk size, MTU, characteristic behavior)?

3. Are there any BLE stack or middleware changes in CubeMX v6.14.0 that could impact OTA functionality, especially when using custom characteristics instead of the default?

This issue is blocking OTA functionality in production, so any clarification or guidance would be greatly appreciated.

Thanks

[STTwo-32 · Accepted solution]

Hello @Dhruvbusa 

Problem has been reproduced and escalated to the concerned team (under internal ticket number 206990). The correction will be on the next release of the app. For now, you can use the STBLESensor - BLE sensor application for Android and iOS - STMicroelectronics and the Web Bluetooth App.

Best Regards.

STTwo-32

[Dhruvbusa]

Thanks, with ST BLE Toolbox v1.4.4, OTA is now working as expected.