Chip card, end unit with chip card and method for modifying a chip card

A chip card or a chip card application, in particular a SIM or a SIM application or a USIM or a USIM application, for use in a terminal device that is assigned to a communications network, having at least one data field containing variable parameter data, said parameter data involving data relative to at least one of identification and authentication of at least one of a user and the terminal device in the communications network, is hereby characterized in that the chip card or the chip card application has an application, in particular an application software, which is implemented on the chip card or in the chip card application, in addition to the at least one data field containing variable parameter data, wherein by means of said application the parameter data can be changed in the at least one data field, in that the application is designed for at least one of generating and providing variable parameter data, that an interface is provided between the application and the at least one data field containing variable parameter data, wherein by means of said interface the parameter data from the application can be written into the data field or parameter data that are present in the data field can be overwritten by the modified parameter data via the interface, and that the chip card or the chip card application has a first startup device for conducting a first startup procedure for subsequent operation of the chip card or the chip card application in an operating mode, and in addition, a second startup device for conducting a second startup procedure for conducting a de-blocking procedure of the chip card or the chip card application, in which the MCC value is set to 001 and the MNC value to 01.