A method for updating firmware of a control device for process control which comprises at least one control module (112, 114), wherein the control module (112, 114) has associated therewith firmware stored in a system memory of the control device, the method comprising the steps of: a) providing a firmware file with a new firmware contained therein for the at least one control module in an updating device that is connectable to the control device; b) retrieving, by the updating device, first device data stored in the control device; c) generating, by the updating device, a signed device file depending on the first device data and depending on an information item identifying the new firmware; d) transmitting the signed device file from the updating device to a central enabling device; e) checking the received signed device file by the central enabling device; f) generating an activation code, by the central enabling device, and transmitting the activation code from the central enabling device to the updating device only if the check of the received signed device file by the central enabling device is successful, wherein the activation code comprises second device data and a unique identification information item; g) performing a consistency check on the first device data retrieved in step b) and on the second device data contained in the received activation code, by the updating device; or again retrieving the first device data stored in the control device, by the updating device, and performing a consistency check on the again retrieved first device data and on the second device data contained in the received activation code, by the updating device; and h) only if the consistency check is successful, performing an update of the firmware of the control device using the new firmware, by the updating device. a) providing a firmware file with a new firmware contained therein for the at least one control module in an updating device that is connectable to the control device; b) retrieving, by the updating device, first device data stored in the control device; c) generating, by the updating device, a signed device file depending on the first device data and depending on an information item identifying the new firmware; d) transmitting the signed device file from the updating device to a central enabling device; e) checking the received signed device file by the central enabling device; f) generating an activation code, by the central enabling device, and transmitting the activation code from the central enabling device to the updating device only if the check of the received signed device file by the central enabling device is successful, wherein the activation code comprises second device data and a unique identification information item; g) performing a consistency check on the first device data retrieved in step b) and on the second device data contained in the received activation code, by the updating device; or again retrieving the first device data stored in the control device, by the updating device, and performing a consistency check on the again retrieved first device data and on the second device data contained in the received activation code, by the updating device; and h) only if the consistency check is successful, performing an update of the firmware of the control device using the new firmware, by the updating device.