[DFU] How to create dfu using a standalone command

RE: [DFU] How to create dfu using a standalone command

SteveHx — Mon, 23 Feb 2026 15:00:08 GMT

Okay, I'm not sure what you mean by "tagging me", but it's ticket #357526.

RE: [DFU] How to create dfu using a standalone command

Sigurd Hellesvik — Mon, 23 Feb 2026 14:30:28 GMT

[quote user="SteveHx"]This is but one link in a long and winding chain of what should be a very simple process. I do not want to lose the context from above.[/quote]

You can link to this ticket, and you can tag me in the new ticket.
Then we will keep the context, and at the same time keep this ticket tidy.

RE: [DFU] How to create dfu using a standalone command

SteveHx — Mon, 23 Feb 2026 14:25:36 GMT

This is but one link in a long and winding chain of what should be a very simple process. I do not want to lose the context from above.

To get back to brass tacks: I need a simple utility I can offer to an end user of my product containing an nRF52832 or nRF52840 microcontroller, to allow him to update the application firmware in the device. There should be no need for him to install a whole development environment etc.

RE: [DFU] How to create dfu using a standalone command

Sigurd Hellesvik — Mon, 23 Feb 2026 14:18:11 GMT

[quote user="SteveHx"]Error: Failed to install nrfutil-nrf5sdk-tools[/quote]

Could you create a new ticket for this?

RE: [DFU] How to create dfu using a standalone command

SteveHx — Fri, 20 Feb 2026 11:18:23 GMT

Since I just downloaded nrfutil.exe in the past week or so, I would expect all required resources to still be available. When I do

nrfutil install nrf5sdk-tools

The response is

Error: Failed to install nrfutil-nrf5sdk-tools

Caused by:
0: Could not download package
1: failed to download from `developer.nordicsemi.com/.../nrfutil-nrf5sdk-tools-x86_64-pc-windows-msvc-1.0.1.tar.gz`
2: failed to get 200 response from `developer.nordicsemi.com/.../nrfutil-nrf5sdk-tools-x86_64-pc-windows-msvc-1.0.1.tar.gz`, got 410

Okay, so let's see what's going on under the hood. Putting that link in my browser (FireFox), yields:

Gone

The requested resource
/.pc-tools/nrfutil/nrfutil-nrf5sdk-tools-x86_64-pc-windows-msvc-1.0.1.tar.gz
is no longer available on this server and there is no forwarding address. Please remove all references to this resource.

Also tested with Chrome and Edge, same result.

Any system with so many scattered pieces is bound to lose a few now and then. But where did it go?

RE: [DFU] How to create dfu using a standalone command

Sigurd Hellesvik — Fri, 20 Feb 2026 10:05:44 GMT

[quote user="SteveHx"]but nrfutil list shows me zero commands installed. [/quote]

Correct. nrfutil is a tool manager that lets you install multiple tools with it.

Do "nrfutil search" to list alternatives and then "nrfutil install ..." for what you need.

If Im correct and you need nRF5 SDK DFU, you can do

nrfutil install nrf5sdk-tools

and then use "nrfutil nrf5sdk-tools ..." as described in nrf5sdk-tools: Generating DFU packages.

If you need more help with nRF5 SDK DFU, could you open a new ticket for it?
This is because this ticket is originally about nRF Connect SDK DFU, so let's try to not confuse future readers of this ticket.

RE: [DFU] How to create dfu using a standalone command

SteveHx — Thu, 19 Feb 2026 21:08:02 GMT

Further clarification: The immediate need is for an nRF52840 system, but I also have nRF52832 based systems in the field that could benefit.

RE: [DFU] How to create dfu using a standalone command

SteveHx — Thu, 19 Feb 2026 21:05:44 GMT

Back at this after a couple days with other distractions. I've read thru the above links, and tried to follow them, but I hit dead ends everywhere. I downloaded nrfutil.exe, but nrfutil list shows me zero commands installed. Where can I download the commands, and why is it a dead end as downloaded?

To clarify, I don't need to DFU a bootloader, nor probably even the softdevice. Both of those will be in the device when shipped. I just need to be able to have a relatively novice user be able to update the application firmware. I should be able to provide an executable and a hex file, or even better, an executable with my hex file embedded, that the user can run to update the application firmware.

RE: [DFU] How to create dfu using a standalone command

longo92 — Tue, 17 Feb 2026 13:17:18 GMT

That's fine, in fact imgtool is standlone and can be downloaded as python package:

https://pypi.org/project/imgtool/

Why don't you think to make also https://github.com/nrfconnect/sdk-nrf/blob/v3.2.1/scripts/bootloader/generate_zip.py as stand-alone python package (along with its dependecies)?

Also this one https://github.com/nrfconnect/sdk-nrf/blob/v3.2.1/scripts/generate_psa_key_attributes.py for creating public keyfile would be useful to have as stand-alone pyhon package (need for client to generate the public key file).

You will easily resolve the needs of most users to have such tool, without digging in nrf repository to find that script....

RE: [DFU] How to create dfu using a standalone command

Sigurd Hellesvik — Tue, 17 Feb 2026 13:13:52 GMT

And a follow-up for Steve:

If you are using Segger, that likely means that you are on the nRF5 SDK.
In this case, you can use nrfutil to generate DFU packages for your application. See nrf5sdk-tools: Generating DFU packages docs

RE: [DFU] How to create dfu using a standalone command

Sigurd Hellesvik — Tue, 17 Feb 2026 13:11:48 GMT

In short: Exactly what you are looking for does not exist.
However, you should be able to achieve what you need, but it will require some effort.

[quote user="longo92"].i would expcet that nrfutil embeds those utilities..[/quote]

nrfutil does not support signing binaries for DFU.
It did support this for the legacy nRF5 SDK bootloader, but not for the nRF Connect SDK. => We can rule out nrfutil as an opetion for a standalone script.

[quote user="longo92"]

Let’s suppose:

I need to design, for a client, a hardware/firmware system based on the nRF54.
During the production phase, the client wants to manage their own private/public keys for firmware signing.
At each firmware release, I will provide the client with unsigned images.
The client must then sign the images and create the DFU package independently.

How can they do this without downloading the entire nRF Connect SDK?

[/quote]

This use-case makes sense to me, and why you do not want to have to download the nRF Connect SDK.

imgtool.py is the script you need for this. imgtool has dependencies on python and some pip packages, yes.
However, python and pip packages are common developer tools, and personally I would argue that it is within reason to expect developers to be able to run python scripts.

If you do not want the signer to have to install python or pip packages, you are free to include imgtool.py into a stand-alone tool you make yourself, which matches your requirements. I think for example "pyinstaller" is one tool that could help with this.
PS: I found "pyinstaller" with a web search, so do take this suggestion with a pinch of salt.

EDIT: Also see that imgtool is a standalone package, as longo remarked as a response to this comment.
Referenced as such:

[quote user="longo92"]

That's fine, in fact imgtool is standlone and can be downloaded as python package:

https://pypi.org/project/imgtool/

[/quote]

RE: [DFU] How to create dfu using a standalone command

SteveHx — Tue, 17 Feb 2026 12:33:43 GMT

I concur. I don't need complexity for the sake of complexity. I just want an app that can take the hex file output of the build tools, and program it using DFU into a processor that already has the required bootloader. I have many projects I need to continue supporting using Segger, but will take a look at moving to Zephyr.

RE: [DFU] How to create dfu using a standalone command

longo92 — Tue, 17 Feb 2026 10:26:28 GMT

Ok- but i do not think that my case is so uncommon...i would expcet that nrfutil embeds those utilities...

RE: [DFU] How to create dfu using a standalone command

Turbo J — Tue, 17 Feb 2026 10:17:45 GMT

Bad idea. You just experienced why - the resulting mess will be very difficult to maintain. SDKs are moving targets...

Since your client is not an end user I don't see the problem with installing NCS SDK and toolchain. Makes all the dependency tracking a lot simpler since it everything was already included.

I rather waste a couple of GB worth of HDD space instead of waiting a few extra weeks for the deliverables.

RE: [DFU] How to create dfu using a standalone command

longo92 — Tue, 17 Feb 2026 09:48:59 GMT

Let’s suppose:

I need to design, for a client, a hardware/firmware system based on the nRF54.
During the production phase, the client wants to manage their own private/public keys for firmware signing.
At each firmware release, I will provide the client with unsigned images.
The client must then sign the images and create the DFU package independently.

How can they do this without downloading the entire nRF Connect SDK?

RE: [DFU] How to create dfu using a standalone command

Sigurd Hellesvik — Tue, 17 Feb 2026 09:35:46 GMT

Let us take a step back here:

Why do you need a standalone app to generate the file for DFU?
The easiest way is normally to get the automatically generated zephyr.signed.bin.
Let's have a look at why this method is not a good fit for you, and we can hopefully find out which solution is best for your use-case

RE: [DFU] How to create dfu using a standalone command

SteveHx — Mon, 16 Feb 2026 19:55:44 GMT

You're on the right track, but this rabbit hole has a lot of blind alleys. I was able to download and install Python, but now I'm stuck on finding Pip3. I would really like to find or create a simple Windows app that my customer could use to program a simple hex file via DFU to my target (currently nRF52840, could be 52832 on future products). Just using this for field firmware updates.

RE: [DFU] How to create dfu using a standalone command

Sigurd Hellesvik — Mon, 16 Feb 2026 15:54:50 GMT

Hi all,

To keep it simple, I will assume the case is for an application with MCUboot as an immutable bootloader.

TL;DR: To manually generate files for DFU, use imgtool.py.

zephyr.signed.bin

To update an application with MCUboot, you need zephyr.signed.bin. This file is automatically generated by our build system, as part of the Output Build Files.

You can generate your own signed binary manually using imgtool.py if you prefer. If you do this, you can start with build/<app>/zephyr.hex, which is your application.

To learn how to upload zephyr.signed.bin to a device to perform DFU, see DevAcademy -> nRF Connect SDK Intermediate -> Lesson 9 on DFU.

dfu_application.zip

Some places you see dfu_application.zip being generated and used, such as in the DevAcademy course for FOTA. However, in this case, dfu_application is not used directly by the SoC. Instead, dfu_application contains zephyr.signed.bin and a manifest json file. The application responsible for the DFU, for example nRF Connect for Mobile or nRF Cloud, will then unzip this file, and DFU the containing zephyr.signed.bin as instructed in the manifest file. This method is useful for more flexible DFU solutions, such as multi image DFU.

The script you refer to is used to generate dfu_application.zip from already signed binary files.

Regards,
Sigurd Hellesvik

RE: [DFU] How to create dfu using a standalone command

SteveHx — Fri, 13 Feb 2026 15:32:46 GMT

That answer is not helpful. I too am trying to get to a standalone DFU installer, or a C file I can add to a PC application to allow an end user to do firmware updates as needed. The instructions for nrfutil are convoluted and do not work, even just to generate a zipfile let alone to program it. This is a deep rabbit hole so far. I need to be able to provide the user a single file, either a .hex file or the .zip that is ostensibly generated by nRFUtil, and a simple way to send that to the device (nRF52832 or nRF52840), preferably via USB. Surely this is not an unusual request, and Nordic's developers should be able to provide a simple and useful answer.

RE: [DFU] How to create dfu using a standalone command

Turbo J — Mon, 09 Feb 2026 14:07:25 GMT

That is a python script, which you can trivially turn into an .exe executable with pyinstaller.