RE: NRF 5340 programmed but will not run

Kazi Afroza Sultana — Mon, 20 Oct 2025 09:28:21 GMT

Hello,

I think the first thing you can try is to recover the device by nrfjprog --recover which will

Perform an ERASEALL via the CTRL-AP
Program the required firmware before a reset is executed; source: Allowing debugger access to nRF5340 - Blogs - Nordic Blog - Nordic DevZone

Because nRf5340 requires firmware to explicitly enable debugger access on every boot.

When we do nrfjprog --recover, it works for both. If it does not work you can try separate reset and erasell by nrfjprog.

Besides this I would like to know if you have external low frequency crystal on your custom board. If not, you have to set internal RC in the prj.conf file of the application

CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y
CONFIG_CLOCK_CONTROL_NRF_K32SRC_500PPM=y
CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC_CALIBRATION=y
CONFIG_CLOCK_CONTROL_NRF_CALIBRATION_LF_ALWAYS_ON=y

You can try these and let me know if these help.

Thanks.

Kazi

RE: NRF 5340 programmed but will not run

Mike Amend — Fri, 17 Oct 2025 15:28:16 GMT

Ticket initiated for NRF 5340 Power Up issue.