https://devzone.nordicsemi.com/f/nordic-q-a/91492/what-meta-data-can-i-pull-from-a-9160-delta-modem-update-bin-fileHello! I&#39;m implementing a 9160 modem update system in our application. I&#39;d like to be able to do some verification steps on my file prior to commencing the update. Ideally this would include verifying the file: is a legitimate delta file and isen-USTelligent Community 13Thu, 01 Sep 2022 08:44:09 GMThttps://devzone.nordicsemi.com/thread/384280?ContentTypeID=1Thu, 01 Sep 2022 08:44:09 GMT137ad170-7792-4731-bb38-c0d22fbe4515:0ee20604-79aa-4c83-a19b-675b3d31aa62Didrik Rokhaug<p>Hi,</p> <p>I had to check this with our modem team, and this is the reply I got:</p> <ul> <li>Only the modem can decrypt, authenticate and integrity check the delta image. <ul> <li>Offline operation is not possible.</li> <li>The modem will respond with a failure response as early in the download process as possible, so if e.g. data is corrupted in transit, it will be detected by the modem no later than after 8 kBytes of additional data has been transferred.</li> </ul> </li> <li>The modem will verify that the delta image targets the on-board firmware during the transfer of the first 8 kBytes.</li> <li>It is the responsibility of the infrastructure outside the modem to pass the correct delta image to the modem.</li> <li>The delta update area in the modem is not used for any other purpose, so for each firmware release, we know how much scratch area there is in all devices with that firmware release. Our modem firmware build process cannot generate a delta image that would not fit.</li> </ul> <p>Best regards,</p> <p>Didrik</p> <p>P.S. I will be out-of-office tomorrow, so I will not be able to provide further replies until Monday. Sorry for the inconvenience.</p><div style="clear:both;"></div>