When downloading source code from a remote Git repository, the download operation fails with errors similar to the following:
PetaLinux 2014.2 has changed from previous versions and now uses the git archive operation when retrieving remote source code.
GitHub does not support archiving when retrieving repositories.
See this GitHub answer for more details: https://help.github.com/articles/can-i-archive-a-repository
A simple workaround is to perform a standard git clone operation of the repository to a known location.
Once the clone is completed, it can be pointed to using the same remote feature in the PetaLinux 2014.2 menuconfig but specifying file://<path_on_disk> rather than http://<URL_OF_GIT_REPO>.