Is there any way to use some toolchain with gcc 9.x for Linux ARM platform?
Yes, override the toolchain-gccarmlinuxgnueabi package with a locally download GCC 9.x version as e.g. explained in the “Packages” section of here.
@maxgerhardt thank you for the fast response.
I can override local toolchain by suggested solution.
Is there any way to add this toolchain to some custom registry (cloud preffered) to share this toolchain between developers and CI instances?
Any user can upload arbitrary packages to the PlatformIO registry (pio package publish) and reference them by username and package name, e.g.
platform_packages =
maxgerhardt/toolchain-gccarmlinuxgnueabi@~1.90000.0
(If I had uploaded that package under my account of the appropriate version).
It is also possible to upload the package to a repository and reference it by the git link. Or HTTPS, etc.
Primarily though you should be asking that at Issues · platformio/platform-linux_arm · GitHub so that it just gets uploaded by PlatformIO staff.