Exercise 4 – Invoking a firmware update over Bluetooth LE (OTA)
In the previous exercises, you set up remote diagnostics, explored the automatically collected Bluetooth LE metrics, and observed how connection parameter changes appear in the nRF Cloud dashboard. In this exercise, you will close the loop by preparing a firmware update and delivering it to the device over Bluetooth LE, which is the same workflow you would use to deploy a fix for an issue discovered through remote observability without physical access to the device.
As discussed in a previous topic, nRF Cloud powered by Memfault supports OTA device firmware updates (DFU). The update binary is transferred from a smartphone to the device over the existing Bluetooth LE connection using the Simple Management Protocol (SMP), and MCUboot handles installing the new image after reboot.
Exercise steps
In the GitHub repository for this course, go to the base code for this exercise, found in l7/l7_e4.
1. Review the OTA and bootloader configuration.
1.1 Open prj.conf. The first half of the file contains the Memfault SDK and connection parameter settings from Exercises 1 and 3. The second half adds the configuration needed for OTA updates. Review the new sections below.
SMP BLE transport: these enable the MCUmgr SMP server over Bluetooth, which is the protocol the nRF Connect Device Manager app uses to transfer firmware images to the device:
Device Information Service (DIS): these expose device metadata over Bluetooth LE so the mobile app can identify the device and match it to the correct OTA release:
Memfault device identity: these configure a static device ID and firmware type so that nRF Cloud can associate OTA releases with specific devices. Without a static device ID, the SDK generates one automatically, which would not match the serial number registered in the dashboard:
Firmware version strings: these three options must always match each other. They set the firmware version reported to Bluetooth LE clients, to nRF Cloud, and to the MCUboot image signing tool respectively:
1.2 Replace both instances of "your-serial-number" in prj.conf with the serial number of your DK (printed on the sticker on the back of the board, the same one you used in Exercise 1). Also, replace "your-project-key-here" with your nRF Cloud project key from Exercise 1.
2. Enable the MCUboot bootloader.
2.1 Create a new file named sysbuild.conf in the l7_e4 project directory (next to prj.conf) with the following content:
Copy
SB_CONFIG_BOOTLOADER_MCUBOOT=y
Kconfig
This tells the build system to include the MCUboot bootloader in the build. MCUboot manages the image swap: when a new firmware image is written to the secondary flash slot over SMP, MCUboot verifies its signature and swaps it into the primary slot on the next reboot.
3. Build and flash the initial firmware (version 0.0.1).
3.1 In the nRF Connect extension in VS Code, add a build configuration for the nRF54L15 DK. Under the sysbuild setting, make sure Use sysbuild is enabled so that MCUboot is included in the build. Then click Build.
3.2 Once the build completes, click Flash. This flashes both the MCUboot bootloader and your application to the device.
3.3 Open a serial terminal and press the Reset button on the DK. You should see output similar to the previous exercises:
*** Booting My Application ****** Using nRF Connect SDK vX.X.X ***Memfault Demo ApplicationBluetooth initializedAdvertising successfully started
Terminal
Important
Logging over UART is used in this lesson for debugging and learning purposes. Be sure to disable it before moving to production, as we covered the power impact of UART logging in previous lessons.
4. Upload the symbol file for version 0.0.1.
4.1 In the nRF Cloud dashboard, navigate to Software → Symbol Files.
4.2 Upload zephyr.elf from your build directory (located under build/<app_name>/zephyr/zephyr.elf). This allows nRF Cloud to symbolicate any crash data collected from this firmware version.
5. Connect the device and verify data is flowing.
5.1 Open the nRF Connect Device Manager app on your smartphone and connect to your device.
5.2 Navigate to the Logs and Stats tab and verify that you see “Uploaded” chunk messages, confirming that the Memfault Diagnostic Service is streaming data through the smartphone to nRF Cloud.
5.3 In the nRF Cloud dashboard, visit Integration Hub → Processing Log and confirm that events are arriving from your device.
6. Create a new firmware version (0.0.2).
6.1 In prj.conf, update the three version strings to create a new release:
In a production scenario, this is where you would also include the code fix for an issue you discovered through the metric data from Exercises 2 and 3. For example, handling a specific phone model that rejects your connection parameter update request.
6.2 Build the project again but do not flash it. The build produces a file called dfu_application.zip in the build directory. This is the signed update package that will be delivered over the air.
6.3 Upload the new zephyr.elf for version 0.0.2 to Software → Symbol Files in the nRF Cloud dashboard.
7. Create and activate an OTA release in nRF Cloud.
7.1 In the nRF Cloud dashboard, navigate to Software → Releases and click Create Release.
7.2 Set the version number to 0.0.2.
7.3 From the Release details, add an OTA payload. Select nrf54l15dk as the hardware type and main as the Software Type (this matches CONFIG_MEMFAULT_NCS_FW_TYPE in your prj.conf). Upload the dfu_application.zip file from the build directory.
7.4 Activate the release by clicking Activate. Choose default for the target Cohort and Normal for the rollout type. Click Activate to make the release available to your fleet.
8. Install the OTA update over BLE.
8.1 Open the nRF Connect Device Manager app and connect to your device.
8.2 Navigate to the Image tab.
8.3 Tap Check for Updates. The app queries nRF Cloud for the latest available firmware for your device. You should see a message indicating that an OTA update is available.
8.4 Tap Download to download the firmware image to your smartphone.
8.5 Tap Start to begin transferring the new firmware to the device over Bluetooth LE using the SMP protocol. Select Confirm Only when prompted and allow the upgrade process to begin.
8.6 Monitor the progress in the app. The firmware image is transferred in chunks over the Bluetooth LE connection. Once the transfer completes and you see “State: UPLOAD COMPLETE”, the device will reboot to install the new image via MCUboot.
9. Verify the update.
9.1 After the device reboots, reconnect from the nRF Connect Device Manager app.
9.2 Tap Check for Updates again. You should see a message indicating that the device is already up to date.
9.3 In the nRF Cloud dashboard, navigate to Fleet → Devices and select your device. Verify that the current firmware version is 0.0.2.
9.4 Open the device Timeline tab. You should see a reboot event corresponding to the firmware update, along with the software version change from 0.0.1 to 0.0.2.
9.5 Note that the OTA firmware transfer used the same Bluetooth LE connection as the Memfault Diagnostic Service. The throughput of the transfer depended on the negotiated connection parameters (connection interval, data length, MTU) that you examined in Exercise 2. A device with DLE enabled and a larger MTU will complete the OTA transfer faster and with less total radio-on time than one running with default parameters.
9.6 Consider the full workflow you have now practiced across Exercises 1 through 4: setting up remote diagnostics, examining Bluetooth LE metrics from the field, correlating connection parameter changes with power consumption, and deploying a firmware update without physical access to the device. In a production scenario, this cycle (observe, diagnose, fix, deploy) runs continuously throughout the product’s lifetime.
Nordic Developer Academy Privacy Policy
1. Introduction
In this Privacy Policy you will find information on Nordic Semiconductor ASA (“Nordic Semiconductor”) processes your personal data when you use the Nordic Developer Academy.
References to “we” and “us” in this document refers to Nordic Semiconductor.
2. Our processing of personal data when you use the Nordic Developer Academy
2.1 Nordic Developer Academy
Nordic Semiconductor processes personal data in order to provide you with the features and functionality of the Nordic Developer Academy. Creating a user account is optional, but required if you want to track you progress and view your completed courses and obtained certificates. If you choose to create a user account, we will process the following categories of personal data:
Email
Name
Password (encrypted)
Course progression (e.g. which course you have completely or partly completed)
Certificate information, which consists of name of completed course and the validity of the certificate
Course results
During your use of the Nordic Developer Academy, you may also be asked if you want to provide feedback. If you choose to respond to any such surveys, we will also process the personal data in your responses in that survey.
The legal basis for this processing is GDPR article 6 (1) b. The processing is necessary for Nordic Semiconductor to provide the Nordic Developer Academy under the Terms of Service.
2.2 Analytics
If you consent to analytics, Nordic Semiconductor will use Google Analytics to obtain statistics about how the Nordic Developer Academy is used. This includes collecting information on for example what pages are viewed, the duration of the visit, the way in which the pages are maneuvered, what links are clicked, technical information about your equipment. The information is used to learn how Nordic Developer Academy is used and how the user experience can be further developed.
2.2 Newsletter
You can consent to receive newsletters from Nordic from within the Nordic Developer Academy. How your personal data is processed when you sign up for our newsletters is described in the Nordic Semiconductor Privacy Policy.
3. Retention period
We will store your personal data for as long you use the Nordic Developer Academy. If our systems register that you have not used your account for 36 months, your account will be deleted.
4. Additional information
Additional information on how we process personal data can be found in the Nordic Semiconductor Privacy Policy and Cookie Policy.
Nordic Developer Academy Terms of Service
1. Introduction
These terms and conditions (“Terms of Use”) apply to the use of the Nordic Developer Academy, provided by Nordic Semiconductor ASA, org. nr. 966 011 726, a public limited liability company registered in Norway (“Nordic Semiconductor”).
Nordic Developer Academy allows the user to take technical courses related to Nordic Semiconductor products, software and services, and obtain a certificate certifying completion of these courses. By completing the registration process for the Nordic Developer Academy, you are agreeing to be bound by these Terms of Use.
These Terms of Use are applicable as long as you have a user account giving you access to Nordic Developer Academy.
2. Access to and use of Nordic Developer Academy
Upon acceptance of these Terms of Use you are granted a non-exclusive right of access to, and use of Nordic Developer Academy, as it is provided to you at any time. Nordic Semiconductor provides Nordic Developer Academy to you free of charge, subject to the provisions of these Terms of Use and the Nordic Developer Academy Privacy Policy.
To access select features of Nordic Developer Academy, you need to create a user account. You are solely responsible for the security associated with your user account, including always keeping your login details safe.
You will able to receive an electronic certificate from Nordic Developer Academy upon completion of courses. By issuing you such a certificate, Nordic Semiconductor certifies that you have completed the applicable course, but does not provide any further warrants or endorsements for any particular skills or professional qualifications.
Nordic Semiconductor will continuously develop Nordic Developer Academy with new features and functionality, but reserves the right to remove or alter any existing functions without notice.
3. Acceptable use
You undertake that you will use Nordic Developer Academy in accordance with applicable law and regulations, and in accordance with these Terms of Use. You must not modify, adapt, or hack Nordic Developer Academy or modify another website so as to falsely imply that it is associated with Nordic Developer Academy, Nordic Semiconductor, or any other Nordic Semiconductor product, software or service.
You agree not to reproduce, duplicate, copy, sell, resell or in any other way exploit any portion of Nordic Developer Academy, use of Nordic Developer Academy, or access to Nordic Developer Academy without the express written permission by Nordic Semiconductor. You must not upload, post, host, or transmit unsolicited email, SMS, or \”spam\” messages.
You are responsible for ensuring that the information you post and the content you share does not;
contain false, misleading or otherwise erroneous information
infringe someone else’s copyrights or other intellectual property rights
contain sensitive personal data or
contain information that might be received as offensive or insulting.
Such information may be removed without prior notice.
Nordic Semiconductor reserves the right to at any time determine whether a use of Nordic Developer Academy is in violation of its requirements for acceptable use.
Violation of the at any time applicable requirements for acceptable use may result in termination of your account. We will take reasonable steps to notify you and state the reason for termination in such cases.
4. Routines for planned maintenance
Certain types of maintenance may imply a stop or reduction in availability of Nordic Developer Academy. Nordic Semiconductor does not warrant any level of service availability but will provide its best effort to limit the impact of any planned maintenance on the availability of Nordic Developer Academy.
5. Intellectual property rights
Nordic Semiconductor retains all rights to all elements of Nordic Developer Academy. This includes, but is not limited to, the concept, design, trademarks, know-how, trade secrets, copyrights and all other intellectual property rights.
Nordic Semiconductor receives all rights to all content uploaded or created in Nordic Developer Academy. You do not receive any license or usage rights to Nordic Developer Academy beyond what is explicitly stated in this Agreement.
6. Liability and damages
Nothing within these Terms of Use is intended to limit your statutory data privacy rights as a data subject, as described in the Nordic Developer Academy Privacy Policy. You acknowledge that errors might occur from time to time and waive any right to claim for compensation as a result of errors in Nordic Developer Academy. When an error occurs, you shall notify Nordic Semiconductor of the error and provide a description of the error situation.
You agree to indemnify Nordic Semiconductor for any loss, including indirect loss, arising out of or in connection with your use of Nordic Developer Academy or violations of these Terms of Use. Nordic Semiconductor shall not be held liable for, and does not warrant that (i) Nordic Developer Academy will meet your specific requirements, (ii) Nordic Developer Academy will be uninterrupted, timely, secure, or error-free, (iii) the results that may be obtained from the use of Nordic Developer Academy will be accurate or reliable, (iv) the quality of any products, services, information, or other material purchased or obtained by you through Nordic Developer Academy will meet your expectations, or that (v) any errors in Nordic Developer Academy will be corrected.
You accept that this is a service provided to you without any payment and hence you accept that Nordic Semiconductor will not be held responsible, or liable, for any breaches of these Terms of Use or any loss connected to your use of Nordic Developer Academy. Unless otherwise follows from mandatory law, Nordic Semiconductor will not accept any such responsibility or liability.
7. Change of terms
Nordic Semiconductor may update and change the Terms of Use from time to time. Nordic Semiconductor will seek to notify you about significant changes before such changes come into force and give you a possibility to evaluate the effects of proposed changes. Continued use of Nordic Developer Academy after any such changes shall constitute your acceptance of such changes. You can review the current version of the Terms of Use at any time at https://academy.nordicsemi.com/terms-of-service/
8. Transfer of rights
Nordic Semiconductor is entitled to transfer its rights and obligation pursuant to these Terms of Use to a third party as part of a merger or acquisition process, or as a result of other organizational changes.
9. Third Party Services
To the extent Nordic Developer Academy facilitates access to services provided by a third party, you agree to comply with the terms governing such third party services. Nordic Semiconductor shall not be held liable for any errors, omissions, inaccuracies, etc. related to such third party services.
10. Dispute resolution
The Terms of Use and any other legally binding agreement between yourself and Nordic Semiconductor shall be subject to Norwegian law and Norwegian courts’ exclusive jurisdiction.
Switch language?
Progress is tracked separately for each language. Switching will continue from your progress in that language or start fresh if you haven't begun.
Your current progress is saved, and you can switch back anytime.
•Support for nRF54LS05 DK (Available through the early access sampling program) •Support for the nRF54LM20B with Axon NPU for Edge AI applications
Bluetooth LE updates
•Quality of Service module is now production-ready. •New experimental features for RF testing (Direct Test Mode) and low-latency packet handling (LE Flushable ACL).
MCUboot & Partition Manager
•Single-Slot DFU and RAM Load mode are both promoted to fully supported •Partition Manager is officially deprecated in favor of Zephyr's devicetree-based partitioning.
