nrfutil timeout when flashing nrf9151 modem firmware (over USB/IP)

RE: nrfutil timeout when flashing nrf9151 modem firmware (over USB/IP)

Jaagup Averin — Thu, 22 Oct 2026 09:39:08 GMT

Hello,

USB/IP is the path of least resistance for us. We have an internal remote USB solution that we use to remotely access any USB devices over USB/IP. Adding a parallel solution for JLink Remote Server is doable. We might look into this sooner if the worker timeout adjustment is not possible.

UPDATE: I tried the JLink Remote Server also. While it is fast enough in the office WiFi, some remote sites still are too slow and time out. In practice we observe ~20% faster flashing with the server compared to USBIP.

Best,

Jaagup

RE: nrfutil timeout when flashing nrf9151 modem firmware (over USB/IP)

Syed Maysum Abbas Zaidi — Thu, 22 Oct 2026 08:36:53 GMT

Hi,

Thanks for the trace logs. The worker is just slow over USB/IP. When it times out, it is setting up the modem’s RAM security settings, which takes many small J-Link register accesses. Over USB/IP each access crosses the network, so this step takes longer than the 20 s nrfutil waits between progress messages from the worker.

Could you try SEGGER’s J-Link Remote Server instead of USB/IP? That should be more optimized for network communication, and should respond in more "normal" time. nrfutil device supports that through --remote-jlink. I haven’t tested modem firmware programming over a remote probe, so please let us know how it goes.

Also is there a specific reason you use USB/IP rather than the Remote Server?

Best Regards,
Syed Maysum

RE: nrfutil timeout when flashing nrf9151 modem firmware (over USB/IP)

Jaagup Averin — Wed, 21 Oct 2026 12:48:30 GMT

Hey,

Here's the trace logs. The slowness originates from running nrfutil over USB/IP, not from the nrfutil tool itself.devzone.nordicsemi.com/.../7848.fail.txt

One USB transaction may have a latency as high as 100-1000ms depending on network quality, so while bumping the timeout from 20s to 30s might work for our use case, with worse connectivity it could time out again. To be able to configure this timeout with some environment variable or cli option would work great for us.

Best,

Jaagup

RE: nrfutil timeout when flashing nrf9151 modem firmware (over USB/IP)

Syed Maysum Abbas Zaidi — Wed, 21 Oct 2026 12:32:29 GMT

Hi,

Thanks for reaching out. Can you rerun with --log-level trace and send the log again?

We want to see if something seems slow there, or if something specific hangs up. The way nrfutil device works is that nrfutil device launches a separate worker executable to deal with the J-Link interaction for that device. The timeout counts from the last time we received a message from the worker process. Normally we should receive more messages here, it shouldn't just hang up for 20 seconds.

Best Regards,
Syed Maysum