The stm32l5 platforms employ a post build script, platform/ext/target/stm/stm32l5xx/boards/scripts/postbuild.sh, and a flash script, platform/ext/target/stm/stm32l5xx/boards/scripts/TFM_update.sh, working in Linux environment.
Could other environment such as OS X be supported, as it is done for the NXP LPC55S69 ? (in platform/ext/target/nxp/lpcxpresso55s69/scripts/build.sh). In particular for the usage of readlink, OS X requires greadlink.