In this section, we will take a look at Nordic's device firmware update Android library that can be used to upload firmware on an nRF5x series based device. In nRF5x Series Nordic chips and S-series SoftDevices, you can perform OTA device firmware update. Consider, you have a device that features nRF5x SoC and you wrote an Android application to communicate with that device. Using OTA DFU library, you can pull the new firmware from the cloud to the app and wirelessly upgrade the firmware in your device. Refer to the following diagram to understand this flow:
The latest version of Nordic’s OTA DFU library is version 1.3.0 and can be downloaded from here https://github.com/NordicSemiconductor/Android-DFU-Library. From Android library version 1.3.0, Nordic introduced a secure device firmware update mechanism. A detailed description of BLE secure DFU bootloader can found at http://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.sdk5.v12.0.0%2Fble_sdk_app_dfu_bootloader.html&cp=4_0_0_4_3_1.