Dear Nordic Team,
I am working on implementing OTA (Over-The-Air) firmware updates over UART on the nRF54L15 platform. I have been following the "Exercise 1 - DFU over UART" tutorial from the Nordic Developer Academy:
Exercise 1 - DFU over UART - Nordic Developer Academy
I have configured my project according to the exercise. I have attached the following files for your review:
1. prj.conf
/cfs-file/__key/communityserver-discussions-components-files/4/7713.prj.conf
2. sysbuild.conf
/cfs-file/__key/communityserver-discussions-components-files/4/4571.sysbuild.conf
3. sysbuild/mcuboot.conf
/cfs-file/__key/communityserver-discussions-components-files/4/3806.mcuboot.conf
4. sysbuild/mcuboot.overlay
/cfs-file/__key/communityserver-discussions-components-files/4/0410.mcuboot.overlay
5. ophelia4ev_nrf54l15_cpuapp.overlay
My Setup
- Target device: nRF54L15_M33
- UART used for DFU: UART30 (configured in the overlay file)
- DFU tool: AuTerm
- Image file: custom
.signed.binimage
What I Observed
- I connected to the DFU UART (UART30) using AuTerm.
- I uploaded the generated
.signed.binimage. - The upload reaches 100% successfully.
- However, after the upload completes, AuTerm displays the following message:
"Upload finished. Set image state failed. Command not supported (likely MCUboot serial recovery)".

- After the upload reaches 100%, I close the COM port in AuTerm.
- I then open the same UART in my terminal application.
- Finally, I manually reset the board.
Expected Behavior
After resetting the board, I expect MCUboot to boot the newly uploaded application. The new application is configured to print debug messages over the same UART30 interface used for the DFU process, so I expect to see those debug messages on the terminal after the board resets.
Actual Behavior
After resetting the board, no debug messages are printed, and the application does not appear to start.
Request
Could you please review the attached configuration files and let me know if I have missed any required configuration for DFU over UART on the nRF54L15?
Also, could you help me understand why AuTerm reports:
Set image state failed.
Command not supported (likely MCUboot serial recovery).
Is this expected behavior for MCUboot serial recovery, or does it indicate that my DFU configuration is incorrect?
Regards,
Venkata Kishore P

Please try to delete the build folder and rebuild. 