Not able to access debug port via jlink

[Nagari Gopal]

nrfjprog -c 125 --recover --log
[error] [ Client] - Encountered error -102: Command connect_to_emu_with_snr executed for 406 milliseconds with result -102
ERROR: Unable to connect to a debugger.
[error] [ Worker] - An unknown error.
ERROR: JLinkARM DLL reported an error. Try again. If error condition
ERROR: persists, run the same command again with argument --log, contact Nordic
ERROR: Semiconductor and provide the generated log.log file to them.

0333.log.log

[Nagari Gopal]

Hii, using custom board of nrf53 series. Programming debug is showing, but not able to access or write the firmware.

If i try using the nrf connect programmer, its showing like this

2025-12-09T14:03:46.872Z INFO Selected device with the serial number 000601001636
2025-12-09T14:03:46.872Z INFO Using nrfutil device to communicate with target via JLink
2025-12-09T14:03:46.896Z DEBUG Sending event "programmer: device selected"
2025-12-09T14:03:46.896Z DEBUG Sending event "programmer: running nrfutil device"
2025-12-09T14:03:47.051Z DEBUG Sending event "programmer: running nrfutil device"
2025-12-09T14:03:47.175Z INFO Reading readback protection status for Application core
2025-12-09T14:03:47.176Z INFO Reading readback protection status for Application core 0%
2025-12-09T14:03:47.345Z INFO Reading readback protection status for Application core 50%
2025-12-09T14:03:47.345Z INFO Reading readback protection status for Application core 50%
2025-12-09T14:03:47.458Z ERROR Failed "reading readback protection status for application core". Error: code: 1, description: Generic, message: Batch task protection-get failed, Device error: Setting the debug port SELECT register failed while powering up sys and debug regions (Unknown Error in J-Link DLL (error code =-1)).

This might indicate that the debug port is unavailable. Please double-check device power supply and SWD lines, and that SWD isn't disabled
2025-12-09T14:03:47.487Z ERROR Error: Failed with exit code 1.
One or more batch tasks failed:
* 601001636: Device error: Setting the debug port SELECT register failed while powering up sys and debug regions (Unknown Error in J-Link DLL (error code =-1)).

This might indicate that the debug port is unavailable. Please double-check device power supply and SWD lines, and that SWD isn't disabled (Generic)

Message: Batch task protection-get failed, Device error: Setting the debug port SELECT register failed while powering up sys and debug regions (Unknown Error in J-Link DLL (error code =-1)).

This might indicate that the debug port is unavailable. Please double-check device power supply and SWD lines, and that SWD isn't disabled.
2025-12-09T14:03:47.487Z ERROR Error: Failed with exit code 1.
One or more batch tasks failed:
* 601001636: Device error: Setting the debug port SELECT register failed while powering up sys and debug regions (Unknown Error in J-Link DLL (error code =-1)).

This might indicate that the debug port is unavailable. Please double-check device power supply and SWD lines, and that SWD isn't disabled (Generic)

Message: Batch task protection-get failed, Device error: Setting the debug port SELECT register failed while powering up sys and debug regions (Unknown Error in J-Link DLL (error code =-1)).

This might indicate that the debug port is unavailable. Please double-check device power supply and SWD lines, and that SWD isn't disabled.