SQL Server 2012 with SP1 Slipstream ISO images do not install SP1

Hello SQL friends,

With a slipstream Image you can install SQL Server 2012 SP1 directly without the need to install SQL Server 2012 SP1 separately after installation of SQL Serer 2012. Unfortunately, by using the ISO images that were previously posted on MSDN and TechNet, SQL Server 2012 SP1 does not install successfully after you install the image.

https://support.microsoft.com/kb/2783963/en-us

Workaround. After you installed SQL Server 2012 SP1 with one of those ISO images, reinstall SQL Server SP1 again.

Cheers,
Heinz