Question/Issue: I’m using custom Zephyr-based firmware with Edge Impulse integration on an nRF52840 DK. The device advertises using the official Edge Impulse BLE service UUID and characteristics, which allows it to appear in the Edge Impulse mobile app’s scan list—but attempting to connect fails consistently.
Project ID:
666711
Project Name: iVativ-nRF52840DK Edge Impulse Studio Link: Login - Edge Impulse
Context / Use Case: I’m building a motion classification demo using the LIS2DH accelerometer (via I²C) on an nRF52840 DK. My custom firmware is based on example-standalone-inferencing-zephyr and includes:
- Edge Impulse SDK
- Model parameters and
.tflitemodel from project ID666711 - LIS2DH sensor integration
- BLE service UUIDs and characteristics matching the official Edge Impulse BLE firmware
- Built on Windows 11 using Zephyr (nRF Connect SDK)
Steps Taken:
- Customized Zephyr project with LIS2DH support and Edge Impulse model
- Configured BLE with the same service UUIDs/characteristics used in official firmware
- Verified advertising on BLE scanner (shows up as “Edge Impulse”)
- Device appears in Edge Impulse mobile app (Android 15)
- Selecting device → connection attempt fails
Expected Outcome: App should connect to the DK and enable BLE data streaming.
Actual Outcome: Device is visible but fails to connect.
Reproducibility: 
Always 
Sometimes Rarely
Environment:
- Device: Nordic nRF52840 DK
- OS (Mobile): Android 15
- Build OS: Windows 11
- BLE Stack: Zephyr (via nRF Connect SDK)
- App: Edge Impulse (latest version from Play Store)
- Firmware Base:
example-standalone-inferencing-zephyr(custom build)
Logs/Attachments:
[Include any logs or screenshots that may help in diagnosing the issue]
Additional Notes: The BLE service UUID and GATT characteristics used in my firmware match those from the official Edge Impulse firmware. Are there other protocol or service-level expectations that the Edge Impulse app depends on during connection?