The building process produces each time an :term:`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 |NCS| build system places output images in the :file:`<build folder>` folder when using sysbuild.
Note
Pass the :ref:`optional parameter <optional_build_parameters>` -vvv to west build to enable a more detailed :ref:`zephyr:west-building-verbose` log, which includes the full commands used by the build system to generate the output build files.
The following table lists build files that can be generated as output when building firmware for supported :ref:`board targets <app_boards>`. The table includes files for single-core and multi-core programming scenarios for both |VSC| 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 |
|---|---|---|
| :file:`zephyr.hex` | Default full image.
In a project with multiple images, several :file:`zephyr.hex` files are generated, one for each image.
zephyr is the value of :kconfig:option:`CONFIG_KERNEL_BIN_NAME`.
The file is located in the :file:`build/<your_application_name>/zephyr` directory. |
|
| :file:`merged.hex` | The result of merging all HEX files for all images for a specific core In multi-core builds, several :file:`merged_<core>.hex` fields are generated, where <core> indicates the CPU core. |
|
| :file:`tfm_s.hex` | Secure firmware image created by the TF-M build system in the background of the Zephyr build. It is used together with the :file:`zephyr.hex` file, which is intended for the Non-Secure Processing Environment (NSPE). Located in :file:`build/tfm/bin`. | Programming :ref:`SPE-only <app_boards_spe_nspe>` and multi-core board targets. |
| :file:`zephyr.signed.bin` | Image update file used to create :file:`dfu_application.zip` for multi-core DFU.
Can also be used standalone for a single-image DFU.
Contains the signed version of the application.
This file is transferred in the real-life update procedure, as opposed to HEX files
that are transferred with nrfjprog when emulating an update procedure.
:ref:`Compatible with MCUboot <mcuboot:mcuboot_ncs>`.
zephyr is the value of :kconfig:option:`CONFIG_KERNEL_BIN_NAME`.
The file is located in the :file:`build/<your_application_name>/zephyr` directory. |
DFU process for single or multi-core board targets |
| :file:`zephyr.signed.hex` | HEX file variant of the :file:`<file_name>.signed.bin` file.
Can also be used standalone for a single-image DFU.
Contains the signed version of the application.
:ref:`Compatible with MCUboot <mcuboot:mcuboot_ncs>`.
zephyr is the value of :kconfig:option:`CONFIG_KERNEL_BIN_NAME`.
The file is located in the :file:`build/<your_application_name>/zephyr` directory. |
Programming single or multi-core board targets |
| :file:`zephyr.signed.encrypted.bin` | Image update file used to create :file:`dfu_application.zip` for encrypted multi-core DFU updates.
Can also be used standalone for a single-image DFU.
Contains the signed and encrypted version of the application.
This file is transferred in the real-life update procedure, as opposed to HEX files
that are transferred with nrfjprog when emulating an update procedure.
:ref:`Compatible with MCUboot <mcuboot:mcuboot_ncs>`.
zephyr is the value of :kconfig:option:`CONFIG_KERNEL_BIN_NAME`.
The file is located in the :file:`build/<your_application_name>/zephyr` directory. |
DFU process for single or multi-core board targets |
| :file:`zephyr.signed.encrypted.hex` | HEX file variant of the :file:`<file_name>.signed.encrypted.bin` file.
Can also be used standalone for a single-image DFU.
Contains the signed and encrypted version of the application.
:ref:`Compatible with MCUboot <mcuboot:mcuboot_ncs>`.
zephyr is the value of :kconfig:option:`CONFIG_KERNEL_BIN_NAME`.
The file is located in the :file:`build/<your_application_name>/zephyr` directory. |
Programming single or multi-core board targets |
| :file:`zephyr.signed.bin` in :file:`mcuboot_secondary_app/zephyr` folder | Secondary slot variant of the :file:`zephyr.signed.bin` file.
:ref:`Compatible with MCUboot <mcuboot:mcuboot_ncs>` in the :doc:`direct-xip mode <mcuboot:design>`.
zephyr is the value of :kconfig:option:`CONFIG_KERNEL_BIN_NAME`. |
DFU process for single-core board targets. |
| :file:`zephyr.signed.hex` in :file:`mcuboot_secondary_app/zephyr` folder | Secondary slot variant of the :file:`zephyr.signed.hex` file.
:ref:`Compatible with MCUboot <mcuboot:mcuboot_ncs>` in the :doc:`direct-xip mode <mcuboot:design>`.
zephyr is the value of :kconfig:option:`CONFIG_KERNEL_BIN_NAME`. |
Programming single-core board targets. |
| :file:`dfu_application.zip` | 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. |
| :file:`matter.ota` | :ref:`ug_matter`-specific OTA image that contains a Matter-compliant header and a DFU multi-image
package that bundles user-selected firmware images.
matter.ota is the value of SB_CONFIG_MATTER_OTA_IMAGE_FILE_NAME. |
DFU over Matter for both single-core and multi-core applications. |
| :file:`<file_name>.zigbee` | :ref:`ug_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: :file:`127F-0141-01020003-light_switch.zigbee`. | DFU over Zigbee for both single-core and multi-core applications in the |NCS| v2.0.0 and later. |
| :file:`<version_string>_<number>.bin` in :file:`lwm2m_carrier_divided_dfu` folder | Set of application update images specific for :ref:`liblwm2m_carrier_readme`. It is required for the
divided FOTA procedure in the SoftBank network.
See :kconfig:option:`CONFIG_LWM2M_CARRIER_SOFTBANK_DIVIDED_FOTA` for more information.
The <version_string> is the value of SB_CONFIG_LWM2M_CARRIER_DIVIDED_DFU_VERSION.
The <number> is a zero-padded three digit number that corresponds to the number of the file in the
update sequence. For example: :file:`versionA_001.bin`. |
Divided FOTA over LwM2M using the :ref:`liblwm2m_carrier_readme` library for single-core applications certified in the SoftBank network. |
Note
MCUboot's :doc:`direct-xip mode <mcuboot:design>` 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 :ref:`more information <ug_nrf52_developing_ble_fota_mcuboot_direct_xip_mode>` section of the :ref:`ug_nrf52_developing` page.
| File | Description |
|---|---|
| :file:`dfu_application.zip` | Contains the following:
|
| :file:`dfu_mcuboot.zip` | 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 (SB_CONFG_SECURE_BOOT_MCUBOOT_VERSION),
:ref:`bootloader` (NSIB) version number (:kconfig:option:`CONFIG_FW_INFO`), board type. This file can be used by FOTA servers (for example, nRF Cloud) to serve both s0 and s1 to the device.
The device can then select the firmware file for the slot that is currently not in use.
Created when the options SB_CONFIG_SECURE_BOOT_APPCORE and SB_CONFIG_BOOTLOADER_MCUBOOT are set. |
| :file:`zephyr.signed.bin` | Signed variant of the firmware in binary format (as opposed to HEX).
It can be uploaded to a server as a FOTA image.
zephyr is the value of :kconfig:option:`CONFIG_KERNEL_BIN_NAME`. |
| :file:`signed_by_mcuboot_and_b0_mcuboot.bin` | 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. |
| :file:`signed_by_mcuboot_and_b0_s1_image.bin` | 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. |
| :file:`zephyr.signed.hex` | 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.
zephyr is the value of :kconfig:option:`CONFIG_KERNEL_BIN_NAME`. |
| :file:`zephyr.signed.bin` in :file:`mcuboot_secondary_app/zephyr` folder | Secondary slot variant of the :file:`zephyr.signed.bin` file intended for use when MCUboot is in the :doc:`direct-xip mode <mcuboot:design>`.
Created when the :kconfig:option:`CONFIG_BOOT_BUILD_DIRECT_XIP_VARIANT` Kconfig option is enabled.
zephyr is the value of :kconfig:option:`CONFIG_KERNEL_BIN_NAME`. |
| :file:`zephyr.signed.hex` :file:`mcuboot_secondary_app/zephyr` folder | Secondary slot variant of the :file:`zephyr.signed.hex` file intended for use when MCUboot is in the :doc:`direct-xip mode <mcuboot:design>`.
Created when the :kconfig:option:`CONFIG_BOOT_BUILD_DIRECT_XIP_VARIANT` Kconfig option is enabled.
zephyr is the value of :kconfig:option:`CONFIG_KERNEL_BIN_NAME`. |
The following table lists secondary build files that can be generated when building firmware update packages using the :ref:`Software Updates for Internet of Things (SUIT) DFU procedure <ug_nrf54h20_suit_intro>`.
| File | Description |
|---|---|
:file:`root_with_binary_nordic_top.yaml.jinja2` |
SUIT Manifest templates automatically placed in the sample directory after the first build of the :ref:`nrf54h_suit_sample` 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 :ref:`nrf54h_suit_sample` sample. The :file:`root.suit` contains embedded application core manifest (:file:`application.suit`) and radio core manifest (:file:`radio.suit`). The :file:`radio.suit` is not generated for the UART version of the :ref:`nrf54h_suit_sample`. These files can be found in the :file:`build/zephyr` directory after building the sample. |
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 |
|---|---|
| :file:`zephyr.elf` | An ELF file for the image that is being built. Can be used for debugging purposes. |
| :file:`zephyr.meta` | 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 -dirty
to the relevant version field. |
| :file:`tfm_s.elf` | An ELF file for the TF-M image that is being built. Can be used for debugging purposes. |
| :file:`manifest.json` | Output artifact that uses information from the :file:`zephyr.meta` output file. |
| :file:`dfu_multi_image.bin` | 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 :ref:`ug_matter` and :ref:`ug_zigbee` protocols. |
| :file:`signed_by_b0_mcuboot.bin` | Intermediate file only signed by NSIB. |
| :file:`signed_by_b0_s1_image.bin` | Intermediate file only signed by NSIB. |