SW4STM32 and SW4Linux fully supports the STM32MP1 asymmetric multicore Cortex/A7+M4 MPUs

   With System Workbench for Linux, Embedded Linux on the STM32MP1 family of MPUs from ST was never as simple to build and maintain, even for newcomers in the Linux world.
And, if you install System Workbench for Linux in System Workbench for STM32 you can seamlessly develop and debug asymmetric applications running partly on Linux, partly on the Cortex-M4.
You can get more information from the ac6-tools website and download two short videos (registration required) highlighting:

System Workbench for STM32

SW4STM32 plugin with Eclipse build error - "read in flex scanner failed"


I am using the latest version with Eclipse together with the SW4STM32 plug-in. I import a project created with STM32CubeMX, and with the chosen toolchain / IDE as SW4STM32. My hardware is an STM32F746G-Disco.

The first time building the project, I get a lot of errors which can be solved by specifying the processor with “-mcpu=cortex-m7”. After that, the only compilation error remaining relates to invoking the MCU GCC Linker.

Below is the full console output from invoking the linker. I have reinstalled the Eclipse software and SW4STM32 plugin and recreated the project many times but the error remains. Is there something that is not specified when creating the project that I need to add?

Building target: stmconnect.elf
Invoking: MCU GCC Linker
arm-none-eabi-gcc -mcpu=cortex-m7 -mthumb -mfloat-abi=soft -L”/Users/USER/Documents/test-workspace/stmconnect/Middlewares/ST/AI/Lib” -specs=nosys.specs -specs=nano.specs -T”../” -Wl,-Map=output.map -Wl,--gc-sections -o “stmconnect.elf” @”objects.list” -lm
/Applications/Eclipse.app/Contents/Eclipse/plugins/fr.ac6.mcu.externaltools.arm-none.macos64_1.17.0.201812190825/tools/compiler/bin/../lib/gcc/arm-none-eabi/7.3.1/../../../../arm-none-eabi/bin/ld: read in flex scanner failed

collect2: error: ld returned 1 exit status

make: *** stmconnect.elf Error 1
“make all” terminated with exit code 2. Build might be incomplete.

10:26:51 Build Failed. 2 errors, 0 warnings. (took 508ms)

Thank you,


I think the Linker Script (-T) is missing in the project properties. Go in the project Properties > C/C++ Build > Settings > Tools Settings > MCU GCC Linker > General, then enter *.ld file from your project.

It is STM32CubeMX which usually set this value... I don’t know why it was not automatically set for your project.


Hello, thank you for the answer, I got it working now.