Abstract: A method and device for changing software in a first memory area in a control unit for controlling operational sequences, the execution of old software parts being replaced by the execution of new software parts and the old software parts being written into the first memory area, the new software parts being written into a second memory area and, due to a first branching in the first memory area, instead of the old software parts being executed in the first memory area, the new software parts are executed in the second memory area, the system, following the execution of the new software parts, branching back again into the first memory area via a second branching in the second memory area and the execution of the other software distinct from the old software parts being continued in the first memory area, the old software parts remaining in the first memory area.