Hi there,
So you can use it to program the Nrf52840 of course or any
JLink ↔ SWD device compatible MCU. The nRF54 can emulate the other 54 series, but not the nrf52 series and While the onboard J-Link (or SEGGER debugger) might technically be capable of programming different Nordic chips, it’s not officially supported to develop nRF52 series code using an nRF54 DK. You’d likely run into issues with the board’s specific memory layout, clock configurations, and peripheral differences.
- To develop and debug nRF52 series code reliably, it’s best to use a DK that features an nRF52 chip (like the nRF52840 DK). That way, you’re working in the correct hardware environment for your target application.
So, although the underlying Nordic SDK can target multiple chips, the DK you use should match the SoC family you intend to develop for.
HTH 
GL 
PJ 