10.2 OTA Image Architecture

The WINC serial Flash can store two copies of the firmware image: a working image and a rollback image. Upon first-time boot, the working image is the factory image and the rollback image will not be available in the WINC Flash. Instead ATE firmware will be available in rollback image firmware section. On performing the OTA firmware upgrade, the ATE firmware will be erased and the newly received firmware will be written into the Roll back image section. The WINC has insufficient internal memory to save the whole image in RAM during an OTA upgrade; therefore, each block of downloaded data is written to the Flash as it is received. In the event that the OTA fails, the existing (Working) image is retained and the rollback image is invalidated. If the transfer succeeds, the Flash control structure is updated to reflect a new working image and the existing image is marked as a valid rollback image.