In a portable data carrier having a non-volatile memory, a memory controller and a memory interface, an effected initial operation of the data carrier is checked through a request to a security unit of the data carrier via a security interface connected to the security unit. For this purpose, the data carrier comprises a memory portion comprising the memory interface and a body portion comprising the security interface, which are interconnected such that the memory portion can be folded out of the body portion, so that simultaneously the memory interface is laid open for a connection to an end device and the electrical connection between the security unit and the security interface is disconnected irreversibly.