We do not have BLE Radio Test firmwaare for RAK5010. Maybe you can try to directly use the CLI command from Nordic Semiconductor? Btw, I am not sure why you are sending an old version of the NRF5 SDK. This should be the latest one.
I tried to develop custom code with ref. to SDK example but it’s not working. RAK5010 outputs on 37,38,39. It’s not getting output on custom selected channe.
Is there any way to porting nRF SDK example code directly in RAK5010 for BLE Radio Test only.
Also please share firmware which you may have used for RAK5010 BLE wireless certification as stated in test reports.