central_hr sample, Undefined references

[jhellen]

Dear all,

I've tried to build the central_hr sample using c:/ncs/v2.9.0/zephyr/samples//bluetooth/hci_ipc for the cpunet. The SDK version is v2.9.0 and the board is nrf5340dk.  It all builds until linking. I get the following undefined references (in red): 

someone any idea? 

Thanks in advance

[jhellen]

The device tree shows 

 *   82  /soc/radio@41008000/bt_hci_sdc

I'm reading something about a softdevice ? Using SDK 2.9.0