*** Update 4/22 SP1 re-release
Stefan's blog has the full download links for SP1 http://blogs.technet.com/b/stefan_gossner/archive/2014/04/22/sp1-for-sharepoint-2013-has-been-rereleased.aspx
And patch again to avoid the lost resources issue - unless you also load April CU. http://support.microsoft.com/kb/2933444
As a precaution due to a recently discovered issue both the SharePoint 2013 and Project Server 2013 Service Pack 1 (SP1) downloads have been temporarily made unavailable. I will post more information when I have it.
“We have recently uncovered an issue with this Service Pack 1 package that may prevent customers who have Service Pack 1 from deploying future public or cumulative updates. As a precautionary measure, we have deactivated the download page until a new package is published.”
The April Cumulative Update is due out next week, and I will be sure to cover in the Cumulative Update release what impact this issue might have, both for customers who have already loaded SP1 and those who have yet to load it..