Just a heads up that the file nRF5_SDK_15.3.0_59ac345/external/micro-ecc/build.sh in SDK 15.3.0 has Windows line endings and thus can't be executed in a terminal:
$./build_all.sh
-bash: ./build_all.sh: /bin/bash^M: bad interpreter: No such file or directory
Converting to unix line endings and then executing it works.
