A method is suggested for updating a memory comprising a first memory area and a second memory area, the method comprising the steps: (a) using a first image of data that is stored in the first memory area while writing a second image of data to the second memory area; (b) switching to using the second image of data that is stored in the second memory area; (c) writing an inverse image of the second image to the first memory area; and (d) using the first memory area and the second memory area as a differential memory. Also, a corresponding device is provided.