A method and an arrangement are provided for updating a first block of digital data (601) by performing a number of update operations which must either all succeed together or all fail together. The number of update operations is greater than or equal to one. A first identifier (TID) is activated (701) which is common to all those update operations that concern the first block of data and must either all succeed together or all fail together. All those update operations are performed (703) that concern the first block of data and must either all succeed together or all fail together. The updated first block of digital data is stored (707) into a logical flash memory device (1101) together with a value that associates the updated first block of data with the first identifier. The first identifier is deactivated (710).