The recommended path for customers running an existing SAP BusinessObjects BI4.0 installation (any patch level) into SAP BusinessObjects BI 4.1 is via the Patch Upgrade.
However, when you install the BI4.1 SP1 Patch or higher on top of BI4.0, this will not automatically add all new features to the deployment. This article will guide you in how you can install new features that have been launched in the BI4.1 (SP1+) release when applying the Patch on top of BI4.0. The updated version of this document now includes the process for a Linux/Unix deployment
Please check out the article: BI4 How To: BI4.0 Patch to BI4.1 SP01+ and adding new features for more details