https://smile.amazon.com/gp/charity/change.html?ie=UTF8&ref_...
And select EFF as your Smile charity. THEN get the browser extension to automatically redirect you to the Smile link:
Chrome: https://chrome.google.com/webstore/detail/smile-always/jgpmh...
Firefox: https://addons.mozilla.org/en-US/firefox/addon/amazonsmilere...
EDIT: I only use the chrome extension, if someone has a better FF extension just let me know and I'll change the link, that was the first one I found.