Why am I having issues when trying to download the Phenix mobile SDKs from Github?

You may not have git LFS (large file storage) installed. Without git LFS, it will download a very small file instead of the actual binaries.

The quickest way to check whether it is installed is by running

git lfs version

If LFS is not installed, see this git article for information on to install it: https://help.github.com/articles/installing-git-large-file-storage/