Hi everyone,
I am running into a persistent debugging issue with a generated STM32Cube AI Studio application on the NUCLEO-N657 board. The debugger seems to drop the connection when transitioning from the "FSBL" to the main application "Appli" , and subsequently locks up.
My Environment:
Board: NUCLEO-N657
IDE: STM32CubeIDE v2.1.1
Tool: STM32Cube AI Studio v1.1.0
Note: The code is generated properly from STM32Cube AI Studio, and the model .hex file is downloaded successfully to the NUCLEO board:
The Issue:
During the first time debugging the program, it starts correctly.
I run the "FSBL" application, and it executes properly.
As soon as the execution jumps from "FSBL" to "Appli", the IDE throws a "Target is not responding" error.
On any subsequent attempts to debug, it does not work at all and throws the error shown in the attached image.
Console:
"STMicroelectronics ST-LINK GDB server. Version 7.13.0
Copyright (c) 2026, STMicroelectronics. All rights reserved.
Starting server with the following options:
Persistent Mode : Disabled
Logging Level : 1
Listen Port Number : 61234
Status Refresh Delay : 15s
Verbose Mode : Disabled
SWD Debug : Enabled
InitWhile : Enabled
Waiting for debugger connection...
Debugger connected
Waiting for debugger connection...
Debugger connected
Waiting for debugger connection...
Target is not responding, retrying...
Shutting down...
Target is not responding, retrying...
Target is not responding, retrying...
Target is not responding, retrying...
Target is not responding, retrying...
"
What I've Tried:
I closely followed the steps outlined in this ST Community article for handling the N657 debugging process, but the issue persists:
How to debug STM32N6 using STM32CubeIDE
These are my configurations:
Build Steps for both the "FSBL" and "Appli" Applications:
"cd "${ProjDirPath}/Debug" && echo y | "C:\Program Files\STMicroelectronics\STM32Cube\STM32CubeProgrammer\bin\STM32_SigningTool_CLI.exe" -bin "${ProjName}.bin" -nk -of 0x80000000 -t fsbl -o "${ProjName}-Trusted.bin" -hv 2.3 -dump "${ProjName}-Trusted.bin" -align"
Has anyone experienced this specific loss of debug connection during the FSBL-to-Application handoff on the N6? Any advice on debugger configuration adjustments or how to recover the target when it gets into this unresponsive state would be greatly appreciated.
Thank you!
