Must toolchain version match SDK version?

[Erlend Isachsen]

Hi.

For a while I have had some issues with the toolchain when using the nRF connect SDK in visual studio code on windows 10. I believe it was after installing SDK version 2.8.0 that I saw the problems first, although I'm not entirely sure. When I use certain commands I get errors in toolchain versions other than 2.8.0. For instance, if I try to build and flash an application using SDK version 1.9.1 and toolchain 1.9.1 I get the attached output.

First of all, is there a workaround to get this to work? I'm currently flashing manually with nrfjprog from command line.

Secondly, should I be matching toolchain versions and SDK versions in the first place? What is the intended/recommended way to use SDK and toolchain versions? If I try build my application with SDK version 1.9.1 and toolchain version 2.8.0 the application appears to run as expected, even with some improvements: resulting merged.hex file is smaller and more warnings are caught in the build process.

Fullscreen error_output.txt Download

[9/27] Linking CXX executable zephyr\zephyr_pre0.elf
[10/27] Generating dev_handles.c
FAILED: zephyr/dev_handles.c
cmd.exe /C "cd /D C:\...\build_191\zephyr && C:\ncs\v1.9.1\toolchain\opt\bin\python.exe C:/ncs/v1.9.1/zephyr/scripts/gen_handles.py --output-source dev_handles.c --kernel C:/.../build_191/zephyr/zephyr_pre0.elf --zephyr-base C:/ncs/v1.9.1/zephyr --start-symbol __device_start"
Traceback (most recent call last):
  File "C:/ncs/v1.9.1/zephyr/scripts/gen_handles.py", line 37, in <module>
    from elftools.elf.elffile import ELFFile
  File "C:\ncs\toolchains\2d382dcd92\opt\bin\Lib\site-packages\elftools\elf\elffile.py", line 41, in <module>
    from ..dwarf.dwarfinfo import DWARFInfo, DebugSectionDescriptor, DwarfConfig
  File "C:\ncs\toolchains\2d382dcd92\opt\bin\Lib\site-packages\elftools\dwarf\dwarfinfo.py", line 17, in <module>
    from .structs import DWARFStructs
  File "C:\ncs\toolchains\2d382dcd92\opt\bin\Lib\site-packages\elftools\dwarf\structs.py", line 10, in <module>
    from logging.config import valid_ident
  File "<frozen zipimport>", line 259, in load_module
  File "logging\config.py", line 30, in <module>
  File "<frozen zipimport>", line 259, in load_module
  File "logging\handlers.py", line 26, in <module>
  File "<frozen zipimport>", line 259, in load_module
  File "socket.py", line 49, in <module>
ImportError: Module use of python312.dll conflicts with this version of Python.
ninja: build stopped: subcommand failed.
FATAL ERROR: re-build

[Edvin]

Hello,

Yes. This is actually a bug. I don't recall the details (but I will dig it up if we can't quickly solve this). Can you please try to install v2.9.0 as well? And if the issue doesn't go away, can you uninstall v2.8.0 (and keep v2.9.0)? Does that change anything?

Best regards,

Edvin

[Erlend Isachsen]

Hi. Thank you for the suggestions, although it didn't seem to change anything.

I tried to install 2.9.0, after which 2.8.0 and 2.9.0 worked but not 1.9.1 as before. Then, I tried to reboot my computer and ended up with the same result. Next, I uninstalled 2.8.0. As before, 2.9.0 worked but not 1.9.1. Restarted by computer again and still the same result. I installed and uninstalled the toolchain versions with the commands in VSCode.

After that, I checked my C:/ncs folder to see that 2.8.0 was still there, and I did not find 2.9.0. So I took the extra step to delete 2.8.0 in my file explorer, uninstall 2.9.0 in VSCode, install 2.9.0 in the toolchain manager and restart my computer. Still the same error as far as I can tell.

On a separate note, I checked my nRF Connect for VS Code extension version (2025.1.127) and found I did not have the april update (which I believe was released today, after my original question?). I see this issue is addressed in this update since it prompts me that support for 1.x.x toolchains is discontinued. It also states "If you are working with the nRF Connect SDK v1.x, select the nRF Connect SDK Toolchain v2.0.0 for your configuration". So I guess the intended strategy is to install toolchain version 2.0.0 and use that for my applications in 1.x.

So I tried this in nRF Connect for VS Code v2025.4.106, but flashing with toolchian verison 2.0.0 does not work either. Without comparing the errors line by line, the error in 2.0.0 appears to be the same as in 1.9.1.

[kreilly]

Hi Edvin,

Here you are!

Fullscreen nrf-connect-support-20250523075905.json Download

// IMPORTANT: The following data can contain sensitive or confidential information about your environment.
// If you do not want others to see this information, make sure to remove it before sharing the data.

// For help and support, visit Nordic Semiconductor's DevZone at https://devzone.nordicsemi.com/.

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Sincerely,

Kieran

[Edvin]

kreilly  and Erlend Isachsen 

Kieran and What happens if you try to take the build configuration that you made using the command line, and flash it from VS Code? Same issue? Or does it succeed?

BR,

Edvin

[kreilly]

Hi Edvin, 

I did attempt this, and it unfortunately fails.

Kieran

[Edvin]

Which part? Flashing the build folder generated from the command line in VS Code? Or flashing from the command line?

[kreilly]

Pressing the flash button from vscode fails on the build configuration, despite working in the command prompt where the ZEPHYR_BASE variable was set in.