quickstart-bluetooth

A production nRF Connect SDK (NCS) application for the nRF Connect for Desktop Quick Start guide. It is the peripheral_lbs sample (button/LED over Bluetooth® LE) with added Memfault observability: the device collects heartbeat metrics and coredumps and serves them over the Memfault Diagnostic Service (MDS) to a phone or desktop gateway, which uploads them to Memfault over HTTPS. The device itself performs no HTTP/TLS.

Supported board: nRF54L15 DK (nrf54l15dk/nrf54l15/cpuapp). This is the only supported target.

What the device does

Control	Behaviour
Button 0	LBS button characteristic - gateway/central sees the press (standard LBS).
Button 1	Demo crash - forces a fault (k_oops) to generate a Memfault coredump. Demo-only.
LED 0	Run status (1 Hz blink - firmware is alive).
LED 1	BLE connection status.
LED 2	LBS LED - controlled by the gateway/central (standard LBS).

Once a gateway connects and the link is secured, the device sends a heartbeat immediately, so it shows up in Memfault within seconds instead of waiting for the periodic interval.

Prerequisites

• The nRF Connect SDK toolchain matching this workspace's NCS base (currently v3.3.x - see the note under Bootstrap). Install it with the Toolchain Manager or nrfutil.
• nrfutil for flashing and reading the device ID.
• A Memfault account and a 32-character project key.

Bootstrap (T2 west workspace)

This repository is the top-level west manifest (T2 star topology). It imports sdk-nrf, which pulls Zephyr and all NCS modules.

west init -m https://github.com/nrfconnect/quickstart-bluetooth my-workspace
cd my-workspace
west update

Note - west version. Run west from the NCS toolchain environment (its west is recent enough for this manifest schema); a system west older than ~v1.2 will reject it. With the Toolchain Manager: nrfutil toolchain-manager launch --ncs-version v3.3.1 -- west update.

Build & flash

west build -b nrf54l15dk/nrf54l15/cpuapp --no-sysbuild project/app
west flash

The single zephyr.hex is the complete image - there is no MCUboot/sysbuild, no DFU (OTA is out of scope).

Provision the Memfault project key

The project key is set over the serial shell and applied on the next boot:

mflt set_project_key <your-32-char-project-key>
kernel reboot cold

mflt set_project_key persists the key, but it is read once at boot - the kernel reboot cold is required for it to take effect. To verify it:

mflt set_project_key
Project key: <your-32-char-project-key>

Security note. The key is stored unencrypted in settings storage (the same at-rest protection as baking it into flash). Runtime provisioning changes how the key arrives, not its confidentiality. For a hardened product, evaluate settings encryption / the nRF54L KMU / TF-M secure storage.

Find the device ID

The Memfault device serial is the FICR device ID. Read it from the PC:

nrfutil device device-info     # or: nrfutil device list

This lets support correlate a physical board with its Memfault device.

Try it end-to-end

1. Connect from a gateway. On mobile, use nRF Toolbox; on desktop, the nRF Connect for Desktop gateway. The link must be secured (paired) - MDS access is gated to the secured connection.
2. The device appears in Memfault within seconds with a reboot report.
3. Press Button 1 to force a crash. After the device reconnects, the gateway uploads the coredump.

Upload symbols for symbolication

Every build has a unique GNU Build ID. Upload the build's zephyr.elf to Memfault so coredumps and traces are symbolicated - without a matching ELF, Memfault shows "Unknown location".

# zephyr.elf is produced next to zephyr.hex in the build directory:
#   build/zephyr/zephyr.elf

Upload it via the Memfault web app (Software → Symbol Files) or the Memfault CLI. Re-upload on every firmware change; the Build ID changes each build.

Releasing

See RELEASE.md for the release process, versioning scheme, and cadence.