nRF9160: HTTP modem delta update

The HTTP modem delta update sample demonstrates how to do a delta update of the modem firmware. A delta update is an update that contains only the code that has changed, not the entire firmware.

The sample uses the FOTA download library to download a file from a remote server and write it to the modem.


The sample supports the following development kit:

Hardware platforms


Board name

Build target

nRF9160 DK




When built for an _ns build target, the sample is configured to compile and run as a non-secure application. Therefore, it automatically includes Trusted Firmware-M that prepares the required peripherals and secure services to be available for the application.

You can also configure it to use the Secure Partition Manager.


The sample connects to an HTTP server to download a signed modem delta image. The delta images are part of the official modem firmware releases. The sample automatically downloads the correct delta image to go from the base version to the test version, or the test version to the base version, depending on the currently installed version.

Building and running

This sample can be found under samples/nrf9160/http_update/modem_delta_update in the nRF Connect SDK folder structure.

When built as a non-secure firmware image for the _ns build target, the sample automatically includes the Trusted Firmware-M (TF-M). You can configure it to use the Secure Partition Manager instead of TF-M.

See Building and programming an application for information about how to build and program the application.


After programming the sample to your development kit,, test it by performing the following steps:

  1. Note the LED pattern (1 or 2 LEDs).

  2. Press Button 1 on the nRF9160 DK or type “download” in the terminal emulator to start the download process of the delta to the alternative firmware version.

  3. Once the download has been completed, follow the reboot instructions printed to the UART console.

  4. Observe that the LED pattern has changed (1 vs 2).

  5. Start over from point 1, to perform the delta update back to the previous version.


This sample uses the following nRF Connect SDK libraries:

It uses the following sdk-nrfxlib library:

It uses the following Zephyr libraries:

In addition, it uses the following secure firmware component: