STM32Cube Debug Jlink GDB Server V1.2.0 is not starting GDB Server

[nobody]

Hello,

With the new STM32Cube Debug Jlink GDB Server V1.2.0 I'm not anymore able to start the debugging session. If I downgrade to V1.1.0 then it is working again. I get always the error message "No GDB Server running". I tried that with my old launch.json settings and with the new generated and adapted json settings.

• Do I miss some special settings or has the new extension a bug?
• Or do i need any dependency?

error message:

 old launch.json

 new launch.json

  

Thanks in advance,
nobody

[Nawres GHARBI]

Hi @nobody 

try to upgrade your jlink FW, this message is generally shown when the FW version is too old comparing to the server

[nobody]

Hi Nawres,

Unfortunately that is not the problem. I updated the Segger J-Trace to latest firmware, but it is still not working.

[Florent V]

Hi @nobody,

For the time being, we cannot reproduce the issue with a Secure/NonSecure U5 project.
Could you please enable the verbose attribute and share the debug console output with us to see if the error is more explicit?
Also, please provide the version of the jlink-gdbserver bundle you are using for your project, which you can find in the Bundles Manager view:

Kind Regards,

/Flo.

[nobody]

First Log

From client: initialize({"clientID":"vscode","clientName":"Visual Studio Code","adapterID":"jlinkgdbtarget","pathFormat":"path","linesStartAt1":true,"columnsStartAt1":true,"supportsVariableType":true,"supportsVariablePaging":true,"supportsRunInTerminalRequest":true,"locale":"en","supportsProgressReporting":true,"supportsInvalidatedEvent":true,"supportsMemoryReferences":true,"supportsArgsCanBeInterpretedByShell":true,"supportsMemoryEvent":true,"supportsStartDebuggingRequest":true,"supportsANSIStyling":true})
To client: {"seq":0,"type":"response","request_seq":1,"command":"initialize","success":true,"body":{"supportsEvaluateForHovers":true,"supportsConfigurationDoneRequest":true,"supportsSetVariable":true,"supportsConditionalBreakpoints":true,"supportsHitConditionalBreakpoints":true,"supportsLogPoints":true,"supportsFunctionBreakpoints":true,"supportsDisassembleRequest":true,"supportsReadMemoryRequest":true,"supportsWriteMemoryRequest":true,"supportsSteppingGranularity":true}}
From client: launch({"name":"Secure & NonSecure App Debugging","type":"jlinkgdbtarget","request":"launch","cwd":"/workspaces/TEST-MCU","preBuild":"${command:st-stm32-ide-debug-launch.build}","runEntry":"main","deviceName":"STM32U5G9NJ","deviceCore":"Cortex-M33","imagesAndSymbols":[{"imageFileName":"/workspaces/TEST-MCU/STM32/TEST_APP/NonSecure/build/TEST_APP_NS.elf"},{"imageFileName":"/workspaces/TEST-MCU/STM32/TEST_APP/Secure/build/TEST_APP_S.elf"}],"verbose":true,"__configurationTarget":6,"__sessionId":"ce370301-99f0-4876-9e9e-a41c1ad139d7"})
From Debug Session: start Launch Sequence
From Debug Session: Step pre-build
From Debug Session: Step validate debug configuration
From Debug Session: Step ST-Link device check
From Debug Session: Step check genuine ST device
From Debug Session: Step start RTOS Proxie(s)
From Debug Session: Step start gdb client debug
To client: {"seq":0,"type":"response","request_seq":2,"command":"launch","success":false,"message":"bound doStepStartGdbClientDebug Failed: GDB Client: No GDB Server running.","body":{"error":{"id":1,"format":"bound doStepStartGdbClientDebug Failed: GDB Client: No GDB Server running.","showUser":true}}}

Then I checked the version, there I saw that the jlink-gdbserver was not installed. Then I installed the gdbserver

  

 Log after installation of jlink-gdbserver and reloaded window

From client: initialize({"clientID":"vscode","clientName":"Visual Studio Code","adapterID":"jlinkgdbtarget","pathFormat":"path","linesStartAt1":true,"columnsStartAt1":true,"supportsVariableType":true,"supportsVariablePaging":true,"supportsRunInTerminalRequest":true,"locale":"en","supportsProgressReporting":true,"supportsInvalidatedEvent":true,"supportsMemoryReferences":true,"supportsArgsCanBeInterpretedByShell":true,"supportsMemoryEvent":true,"supportsStartDebuggingRequest":true,"supportsANSIStyling":true})
To client: {"seq":0,"type":"response","request_seq":1,"command":"initialize","success":true,"body":{"supportsEvaluateForHovers":true,"supportsConfigurationDoneRequest":true,"supportsSetVariable":true,"supportsConditionalBreakpoints":true,"supportsHitConditionalBreakpoints":true,"supportsLogPoints":true,"supportsFunctionBreakpoints":true,"supportsDisassembleRequest":true,"supportsReadMemoryRequest":true,"supportsWriteMemoryRequest":true,"supportsSteppingGranularity":true}}
From client: launch({"name":"Secure & NonSecure App Debugging","type":"jlinkgdbtarget","request":"launch","cwd":"/workspaces/TEST-MCU","preBuild":"${command:st-stm32-ide-debug-launch.build}","runEntry":"main","deviceName":"STM32U5G9NJ","deviceCore":"Cortex-M33","imagesAndSymbols":[{"imageFileName":"/workspaces/TEST-MCU/STM32/TEST_APP/NonSecure/build/TEST_APP_NS.elf"},{"imageFileName":"/workspaces/TEST-MCU/STM32/TEST_APP/Secure/build/TEST_APP_S.elf"}],"verbose":true,"__configurationTarget":6,"__sessionId":"5e3a68fc-e422-4f8d-b645-7b53dc26365f"})
From Debug Session: start Launch Sequence
From Debug Session: Step pre-build
From Debug Session: Step validate debug configuration
From Debug Session: Step ST-Link device check
From Debug Session: Step check genuine ST device
From Debug Session: Step start RTOS Proxie(s)
From Debug Session: Step start gdb client debug
To client: {"seq":0,"type":"response","request_seq":2,"command":"launch","success":false,"message":"bound doStepStartGdbClientDebug Failed: GDB Client: No GDB Server running.","body":{"error":{"id":1,"format":"bound doStepStartGdbClientDebug Failed: GDB Client: No GDB Server running.","showUser":true}}}

For me it's strange that the jlink-gdbserver was not installed, but the gdb-jlink extension was installed.
Any clue what happens?

Thanks a lot
nobody

[Florent V]

The STM32Cube Debug J-Link Gdb Server extension contains the implementation of our Debug Adapter Protocol (DAP) for J-Link as well as the JSON schema for the jlinkgdbtarget debug configuration.
The extension does not include the J-Link gdb server binary. That binary is included in the associated bundle. This allows you to have multiple versions of J-Link gdb server installed on your machine (visible from the bundles manager). So maybe version 9.14 was not installed, but another version was.

That said:

• I see in your screenshots, in the bundles manager view, you only have access to the "system" and not the "project" bundle manager (see my screenshot in my first post). Maybe the project had not yet been imported into VSCode at the time of your screenshots?
• Please check the bundle manager on the project, because that's where you can see which version has been "locked" and is being used for this project. (if an old version is locked, please try to lock the latest installed)
• I also see that the error comes from the fact that the gdb client cannot connect to the gdb server simply because the gdb server was not launched. We don't see the step to launch the gdb server in the debug console trace.

Possible cause:
The project setup did not complete successfully. You can redo it by using "Setup STM32Cube projects" in the STM32Cube Key Actions view.

Best Regards,

/Flo

[Cartu38 OpenDev]

@nobody 
Any chance antivirus pain here ?
See https://community.st.com/t5/stm32cubeide-for-visual-studio/unable-to-install-stlink-gdbserver-with-bundles-manager/td-p/885884

What the following reports to you ?

cube jlink-gdbserver --version

On my side

SEGGER J-Link GDB Server V9.14a Command Line Version

JLinkARM.dll V9.14a (DLL compiled Jan 28 2026 17:11:52)

[nobody]

cube jlink-gdbserver --version
SEGGER J-Link GDB Server V9.14a Command Line Version

JLinkARM.dll V9.14a (DLL compiled Jan 28 2026 17:20:07)

I see almost the same, only the compile time is different.

Antivirus could be a problem, but I think when the old version is working and the new not, then it is probably once not the antivirus.

[nobody]

Mhm, interesting.

I can not do a project setup, that is in my case greyed out. Why is that not possible? The project is from .ioc generated with the cmake option selected.

Were there any changes made, which explains why the old version is working and the new one not anymore?