Hey !
Yes this was my mistake and this morning I decided to start from scratch.
So I’ve redownloaded ubuntu, cloned the repo, launched the “install-prereqs-ubuntu.sh” and at this point I deleted the folder “gcc-arm-none-eabi-10-2020-q4-major-aarch64-linux” that was in /opt and I copied the file “gcc-arm-9.2-2019.12-x86_64-arm-none-linux-gnueabihf.tar.xz”. I did the
tar -xJf gcc-arm-9.2-2019.12-x86_64-arm-none-linux-gnueabihf.tar.xz -C /opt
thing and then I did
echo export ‘PATH=/opt/gcc-arm-9.2-2019.12-x86_64-arm-none-linux-gnueabihf/bin:$PATH’
Finaly I was able to configure my board as navigator and lanch sub (adding the wonderfull --toolchain=… and this time everything seems okay.
I want to thank you all for your help !