Not able to flash nRF54

[summersun]

Hi,

I'm not able to flash nRF54 DK. Log as below:

2025-08-29T06:47:39.828Z INFO Initialising the bundled nrfutil device
2025-08-29T06:47:39.874Z DEBUG Started watching devices
2025-08-29T06:47:42.718Z INFO Using the bundled core version for nrfutil device: 8.1.1
2025-08-29T06:47:42.846Z INFO Using nrfutil-device version: 2.10.2
2025-08-29T06:47:42.847Z INFO Using nrf-device-lib version: 0.17.71
2025-08-29T06:47:42.847Z INFO Using nrf-probe version: 0.38.0
2025-08-29T06:47:42.847Z INFO Using JLink version: JLink_V8.18
2025-08-29T06:47:42.923Z DEBUG Selected device: nRF54L15 DK
2025-08-29T06:47:42.957Z DEBUG Changed step: Info
2025-08-29T06:47:44.231Z DEBUG Changed step: Rename
2025-08-29T06:47:45.203Z DEBUG Changed step: Program
2025-08-29T06:47:59.434Z ERROR [ProbeLib] [2025-08-29 06:47:59.434017Z] Failed to initialize worker: Timed out waiting for response from worker.
2025-08-29T06:48:03.636Z ERROR [ProbeLib] [2025-08-29 06:48:03.637323Z] Trace channel disconnected unexpectedly.
2025-08-29T06:48:03.645Z ERROR [ProbeLib] [2025-08-29 06:48:03.646395Z] Worker exited with error code 1.

[Kazi Afroza Sultana]

Hello,

Try to use the latest version of J-link.

''Use the J-Link v8.42 when working with the nRF Connect SDK, as also listed in the Install prerequisites section on the nRF Connect SDK installation page.''

For nRF54 series devices, nrfutil is required for flashing. Make sure you have the correct and up-to-date version of nrfutil installed globally, as west and other tools rely on it for nRF54 devices. You can check if you hve latest version of nrfutil by this nrfutil --version command. 

By the way which version of DK you are using and which sample/application you are running on the DK?

Thanks.

BR

Kazi

[summersun]

nRF54L15 development kit. it should have debugger onboard and no need external Jlink right?

[Kazi Afroza Sultana]

You need to install correct version of Jlink working with NCS. you can see the j-link information here in the log as well