https://devzone.nordicsemi.com/f/nordic-q-a/51920/dat-file-dfu-packetHi , I would like to know if the .dat file inside the DFU packet is always the same or it can be different. Is it Possible to fix inside the code ? What is the .dat file contains ? Thanks , Lucaen-USTelligent Community 13Tue, 10 Sep 2019 06:58:44 GMThttps://devzone.nordicsemi.com/thread/208801?ContentTypeID=1Tue, 10 Sep 2019 06:58:44 GMT137ad170-7792-4731-bb38-c0d22fbe4515:06425a18-3cb5-456e-b54c-77bbf6a4dd75Einar Thorsrud<p>Hi Luca,</p> <p>the .dat file inside the DFU .zip file contains the <a href="https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v15.3.0/lib_bootloader_dfu_validation.html?cp=5_1_3_5_1_1_0#lib_bootloader_dfu_init">init packet</a>. You can also refer to <a href="https://infocenter.nordicsemi.com/topic/ug_nrfutil/UG/nrfutil/nrfutil_customizing.html?cp=6_5_8">Customizing the init packet</a>&nbsp;in the nrfutil documentation. As you can see from the <a href="https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v15.3.0/lib_bootloader_dfu_validation.html?cp=5_1_3_5_1_1_0#lib_bootloader_dfu_init">documentation</a>, the init packet will depend on the image you are updating, since it contains information like firmware version, hash of the image, signature, SoftDevice dependencies, etc.</p> <p></p> <p>Einar</p><div style="clear:both;"></div>