APPROTECT: Issue with GDB Server and nrf9151

Hi there,

I am trying to debug a nrf9151 with the JLink GDB Server (V8.28). When I select the "nrf9151_xxCA" as target device, the firmware is not flashed to the nrf9151. When I select "nrf9160_xxAA" as target device, I am able to download and debug the application from vscode with the Cortex-Debug plugin.

It looks as if the JLink GDB Server does not flash the device, when I look at the devices memory with J-Mem (V8.28), the device is empty/erased.

I found a thread which looks pretty similar: [ABANDONED] nRF9161 debugging with Ozone
I also found this information, but it did not really help either: https://kb.segger.com/Nordic_Semiconductor_nRF91xx A full erase before debugging is fine for me, so setting the UICR to prevent the APPROTECT setting seems not so relevant for me.

Is this a known issue or am I getting something wrong?

Best regards
Stefan

I have set UICR.APPROTECT and and UICR.SECUREAPPROTECT to 0x50FA50FA and when starting the GDB with target nrf9160_xxAA I can see that these values are written to UICR and I see that my firmware sets APPROTECT.DISABLE and SECUREAPPROTECT.DISABLE to 0x0000005A.

However when I select nrf9151_xxCA as target device the debug port is locked after a attempted download (and reset)