Hello folks,

any time I launch the compile_kernel.sh script the linux-source and rpi_firmware folders and deleted, downloaded again and checked out to a given specific commit..

Shouldn't you fix this behaviour ? I am working on a patch supporting the new RPi 4 board and the arm64 architecture as well...

You should also consider to use the cross-toolchains already residing in the repositories of most popular linux distributions, first of all the debian based, installing them with a simple package manager one liner command (instead of cloning them)...