nrfjprog consumes 100% CPU power

RE: nrfjprog consumes 100% CPU power

Ernestas Gruodis — Wed, 01 Oct 2025 09:59:56 GMT

Thanks, tried nrfutil:

nrfutil device recover --family nrf51 --traits jlink
nrfutil device erase --family nrf51 --traits jlink
nrfutil device program --family nrf51 --traits jlink --firmware fw.hex
nrfutil device fw-verify --family nrf51 --traits jlink --firmware fw.hex
nrfutil device protection-set all --family nrf51 --traits jlink 
nrfutil device reset --family nrf51 --traits jlink

Works perfectly, hope no problems will occur.

RE: nrfjprog consumes 100% CPU power

Kenneth — Wed, 01 Oct 2025 08:09:40 GMT

Hi,

Can you switch to nrfutil and check if you see the same problem there?
https://www.nordicsemi.com/Products/Development-tools/nRF-Util

If you do, then try to explain how we can recreate it, so I can forward it internally to the team. Unfortunately we are not doing much maintenance on the nrfjprog anymore, since we recommend using nrfutil instead. The first you can do is execute "nrfutil self-upgrade" followed by "nrfutil upgrade device", then to program the nRF51822 you can try to call "nrfutil device --help" for a list of parameters.

Kenneth

RE: nrfjprog consumes 100% CPU power

Ernestas Gruodis — Wed, 01 Oct 2025 06:40:16 GMT

The problem is, that it hangs all Windows system.. I suspect it happens when physical SWD contact is lost during / before programming. Seems, that nrfjprog enters into some "while loop".

RE: nrfjprog consumes 100% CPU power

Turbo J — Wed, 01 Oct 2025 06:24:03 GMT

Yes, but it will require a significant redesign of your script/batch file. You can't simply ignore all errors.