Precache, available at https://github.com/krypted/precache, is a script that populates the cache on an OS X Caching server for Apple updates. The initial release supported iOS. The script now also supports caching the latest update for an AppleTV. To use that, there’s no need to include an argument for AppleTV. Instead, you would simply run the script followed by the model identifier, as follows:
sudo python precache.py AppleTV5,4