Output build files (image files)
The building process produces each time an image file.
The image file can refer to an executable, a program, or an ELF file. As one of the last build steps, the linker processes all object files by locating code, data, and symbols in sections in the final ELF file. The linker replaces all symbol references to code and data with addresses. A symbol table that maps addresses to symbol names is created. This table is used by debuggers. When an ELF file is converted to another format, such as HEX or binary, the symbol table is lost.
Depending on the application and the SoC, you can use one or several images.
The nRF Connect SDK build system places output images in the <build folder>
folder when using sysbuild.
Common output build files
The following table lists build files that can be generated as output when building firmware for supported board targets. The table includes files for single-core and multi-core programming scenarios for both Visual Studio Code and command-line building methods. Which files you are going to use depends on the application configuration and not directly on the type of SoC you are using.
File |
Description |
Programming scenario |
---|---|---|
|
Default full image.
In a project with multiple images, several |
|
|
The result of merging all HEX files for all images for a specific core
In multi-core builds, several |
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|
Secure firmware image created by the TF-M build system in the background of the Zephyr build.
It is used together with the |
Programming SPE-only and multi-core board targets. |
|
Image update file used to create |
DFU process for single or multi-core board targets |
|
HEX file variant of the |
Programming single or multi-core board targets |
|
Secondary slot variant of the |
DFU process for single-core board targets. |
|
Secondary slot variant of the |
Programming single-core board targets. |
|
Zip file containing both the MCUboot-compatible update images for one or more cores and a manifest describing its contents. |
DFU process for both single-core and multi-core applications. |
|
Matter-specific OTA image that contains a Matter-compliant header and a DFU multi-image
package that bundles user-selected firmware images.
|
DFU over Matter for both single-core and multi-core applications. |
|
Zigbee-specific OTA image that contains the Zigbee application with the Zigbee OTA header
used for providing information about the image to the OTA server.
The <file_name> includes manufacturer’s code, image type, file version, and comment
(customizable by user, sample name by default).
For example: |
DFU over Zigbee for both single-core and multi-core applications in the nRF Connect SDK v2.0.0 and later. |
MCUboot output build files
Note
MCUboot’s direct-xip mode and the related SB_CONFIG_MCUBOOT_MODE_DIRECT_XIP
and SB_CONFIG_MCUBOOT_MODE_DIRECT_XIP_WITH_REVERT
Kconfig options are currently supported only on the single-core devices such as the nRF52 Series.
For more details, see the more information section of the Developing with nRF52 Series page.
File |
Description |
---|---|
|
Contains the following:
|
|
Contains two versions of MCUboot linked against different address spaces corresponding to slot0 (s0) and slot1 (s1) and a manifest JSON file describing their MCUboot version number ( |
|
Signed variant of the firmware in binary format (as opposed to HEX).
It can be uploaded to a server as a FOTA image.
|
|
MCUboot update image for s0 signed by both MCUboot and NSIB. The MCUboot signature is used by MCUboot to verify the integrity of the image before swapping and the NSIB signature is used by NSIB before booting the image. |
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MCUboot update image for s1 signed by both MCUboot and NSIB. The MCUboot signature is used by MCUboot to verify the integrity of the image before swapping and the NSIB signature is used by NSIB before booting the image. |
|
Signed variant of the firmware in the HEX format.
This HEX file is linked to the same address as the application.
Programming this file to the device will overwrite the existing application.
It will not trigger a DFU procedure.
|
|
Secondary slot variant of the |
|
Secondary slot variant of the |
SUIT output build files
The following table lists secondary build files that can be generated when building firmware update packages using the Software Updates for Internet of Things (SUIT) DFU procedure.
File |
Description |
---|---|
|
SUIT Manifest templates automatically placed in the sample directory after the first build of the SUIT: Device firmware update on the nRF54H20 SoC sample. They serve as the basis for generating the specific SUIT envelopes tailored to the requirements of different domains within the device (root, application, and radio). |
|
Binary SUIT envelopes that are generated from their respective YAML manifest templates during the build process of the SUIT: Device firmware update on the nRF54H20 SoC sample.
The |
Other output build files
The following table lists secondary build files that can be generated when building firmware, but are only used to create the final output build files listed in the table above.
File |
Description |
---|---|
|
An ELF file for the image that is being built. Can be used for debugging purposes. |
|
A file with the Zephyr and nRF Connect SDK git hashes for the commits used to build the application.
If your working tree contains uncommitted changes, the build system adds the suffix |
|
An ELF file for the TF-M image that is being built. Can be used for debugging purposes. |
|
Output artifact that uses information from the |
|
Multi-image package that contains a CBOR manifest and a set of user-selected update images, such as firmware images for different cores. Used for DFU purposes by Matter and Zigbee protocols. |
|
Intermediate file only signed by NSIB. |
|
Intermediate file only signed by NSIB. |