On Debian and derivatives, the package you’re looking for is gcc-arm-none-eabi:

apt install gcc-arm-none-eabi

To find this out yourself in future, install apt-file, update your indexes and use it to search for commands:

apt install apt-file
apt-file update
apt-file search bin/arm-none-eabi-gcc

It turned out that ARM decided to make our life easier (sarcasm) by deprecating the use of PPA - their page at launchpad now has an anouncement: "... all new binary and source packages will not be released on Launchpad henceforth ...".

So, to make use of their latest arm-none-eabi-gdb you have to install gcc-arm-embedded manually.

Remove arm-none-eabi-gcc from your system:

sudo apt remove gcc-arm-none-eabi

Download latest version (Linux x86_64 Tarball) from their website, check its MD5. Unpack it into some directory. I used /usr/share/ :

sudo tar xjf gcc-arm-none-eabi-YOUR-VERSION.bz2 -C /usr/share/

Create links so that binaries are accessible system-wide:

sudo ln -s /usr/share/gcc-arm-none-eabi-YOUR-VERSION/bin/arm-none-eabi-gcc /usr/bin/arm-none-eabi-gcc 
sudo ln -s /usr/share/gcc-arm-none-eabi-YOUR-VERSION/bin/arm-none-eabi-g++ /usr/bin/arm-none-eabi-g++
sudo ln -s /usr/share/gcc-arm-none-eabi-YOUR-VERSION/bin/arm-none-eabi-gdb /usr/bin/arm-none-eabi-gdb
sudo ln -s /usr/share/gcc-arm-none-eabi-YOUR-VERSION/bin/arm-none-eabi-size /usr/bin/arm-none-eabi-size
sudo ln -s /usr/share/gcc-arm-none-eabi-YOUR-VERSION/bin/arm-none-eabi-objcopy /usr/bin/arm-none-eabi-objcopy

Install dependencies. ARM's "full installation instructions" listed in readme.txt won't tell you what dependencies are - you have to figure it out by trial and error. In my system I had to manually create symbolic links to force it to work:

sudo apt install libncurses-dev
sudo ln -s /usr/lib/x86_64-linux-gnu/libncurses.so.6 /usr/lib/x86_64-linux-gnu/libncurses.so.5
sudo ln -s /usr/lib/x86_64-linux-gnu/libtinfo.so.6 /usr/lib/x86_64-linux-gnu/libtinfo.so.5

Check if it works:

arm-none-eabi-gcc --version
arm-none-eabi-g++ --version
arm-none-eabi-gdb --version
arm-none-eabi-size --version

Hello @lotou, · To determine the version of the toolchain used with your CubeIDE, navigate to the directory:  · C:\ST\STM32CubeIDE_1.18.0\STM32CubeIDE\plugins\com.st.stm32cube.ide.mcu.externaltools.gnu-tools-for-stm32.13.3.rel1.win32_1.0.0.202411081344\tools\bin  · Note: adjust the identifiers according to your system. · Open the command prompt and execute the command: ./arm-none-eabi-gcc --version. · This will display the GCC compiler version. You can then download it directly from ARM's website · For example: ARM GNU Toolchain. · Regarding cyclomatic complexity, it measures the number of linear paths, branching points, and loops in your code. Higher complexity increases the likelihood of crashes in your application. By incorporating cyclomatic complexity checks into your build pipeline, you can periodically ensure your solution hasn't regressed into a more failure-prone version. But you should keep in mind that it is not a performance metric of your code. · To know more about the usage of cyclomatic complexity in CubeIDE, refer to UM2609 for CubeIDE, specifically section 4.1 Cyclomatic Complexity. · Please mark my answer as best by clicking on the “Accept as solution" button if it fully answered your question. This will help other users find this solution faster.​