'Operation failed' DFU error in iOS on some rare boards

[QuentinFarizon]

I have opened this ticket on Github a few months ago but it doesn't seem to be maintained anymore : https://github.com/NordicSemiconductor/IOS-DFU-Library/issues/504

Among thousands of customers on iOS, that did tens of thousands of DFU, 25 of our customers get error "Operation failed" when applying DFU, after steps deviceConnecting -> dfuProcessStarting -> enablingDfuMode -> Operation failed

We have had, and continue to have, this error a few times per month since 2021.

On one specific device, 3 dfferent iphones failed to update it.

Everytime the customer found an Android phone to perform the DFU, it worked.

[Menon]

Hello,

I have reported this internally and will get back to you when I have an update from the team.

Kind Regards,

Abhijith

[Aleksander Nowakowski]

Hello,

Sorry for not replying to the GitHub issue. We do maintain it, but we were busy with other projects and have missed that one.

Let me answer in the mentioned GitHub issue, as it's easier to track code from there.

[Aleksander Nowakowski]

I tracked the root cause of the issue to SoftDevice returning an error from here: sd_ble_gatts_hvx(...). I may be wrong. Anyway, as I have no experience with embedded programming I have to end here leaving you in good hands of Menon . 

Please, follow my discoveries here: Getting "Operation failed" on random customers (iOS) · Issue #504 · NordicSemiconductor/IOS-DFU-Library (github.com)

[QuentinFarizon]

Hello, any news ? 

[Menon]

Hello,

Sorry for the long response time. I am not that familiar with old SDK as use our new nRF connect SDK. I need to ask this internally for getting better insight. I will get back to you soon.

Kind Regards,

Abhijith