VSCode Debug broken: Since this morning 9 out of 10 times VSCode debugger sessions start in cmsis_gcc.h not main.c

[cellular_iot]

The same config I was working with the past months and could still debug yesterday morning is not working correctly since this morning. Mostly when I start a debug session its not starting at main of the lwm2m_client sample as before but at 

__STATIC_FORCEINLINE void __set_BASEPRI(uint32_t basePri) cmsis_gcc.h and the app is not working. When I build and flash the exact same config its working fine what I can see in the Seggers RTTViewer. When I load the same zephyr.elf file in Ozone, its just working fine a starting at main() and I can step through.

Whats happening here?

What I treid the past 6 wasted hours:
* created new config: worked 1x then same issue, seems like config settings I do are lost randomly after building, closing configuration window and reopen it
* restarted VSCode: rarely I got a working debug session, mostly not
* close application, open application: same issue
* updated plugins: after nrf connect from 2025-08-21 was installed, all behaved even worse then before
* removed VSCode and deleted all local settings I could find on the Windows 11 PC
* Installed VSCode from Windows 11 App Store
* installed NRF Connect Pack
* created new NRF application from sample - blinky nrf9151ns - build/debug - starts at main()
* opened my existing application I develop the past months (lwm2m_client sample from SDK 3.0.1), build existing configuration, flash - working, debug - halts in cmsis_gcc, not working
* open zephyr.elf in Ozone, flash and debug - starts in main(), single step works just fine.

[Øyvind]

Hello, 

Thanks for reporting and sharing. I will need to discuss internally with our VS  Code team. Could you please share the output from Generate Support information?

Thanks!

Kind regards,
Øyvind

[cellular_iot]

Thanks for looking into this, Øyvind!

Personally, I much prefer using VS Code over Ozone since everything is in one place: I can search through all app and SDK files, build, debug, use the RTT console, the shell, and more.

However: On Windows 11, the VS Code–based nRF Connect experience feels extremely unstable for me. Even basic features often don’t work reliably, or break unexpectedly. It gives the impression that not many people at Nordic are actually using this “recommended setup” on a daily basis…

[Øyvind]

Thank you for reaching out and for the details you've already provided. I understand how frustrating it can be when functionality doesn't work as expected, and I appreciate your efforts in trying to resolve it.

To help us investigate and resolve the issue effectively, we kindly ask for a bit more information. Specifically, logs, screenshots, and any relevant support details (such as your environment setup or error messages) can be incredibly helpful in pinpointing the root cause. Without these, it becomes much more difficult to reproduce or diagnose the problem accurately.

We’re committed to improving your experience and resolving this as quickly as possible, and your input plays a crucial role in that process. If there’s anything we can do to make it easier for you to share this information, please let us know.

Looking forward to your response.

[cellular_iot]

Currently it looks like this may be a side effect of another new bug: https://devzone.nordicsemi.com/f/nordic-q-a/123942/vscode-in-nrfconnect-removes--dconfig_debug_thread_info-y-since-end-of-august-2025 "VScode in nRFConnect removes -DCONFIG_DEBUG_THREAD_INFO=y since end of August 2025"

In order to being able working at all I had to first roll back to pre-August release the past days.

[Øyvind]

Without any logs showing the issue, and no support information, it is very difficult to provide any support to you and pinpoint the issue you are seeing.