TX Power configuration in nrf52832

Hi, we made a custom board with nrf52832 and flashed example code experimental_ble_app_blinky from sdk13.

We are trying to change the radio txpower other than 0db (default value).

While trying to set the values in radio txpower register before ble_stack_init() in main function, the value have been set.

But when I am reading the register value at the end of main(), it is reading default value(0db is set).

And while trying to set the values in radio txpower register after ble_stack_init() in main(), fatal error occurs.

Is there any dependency for setting TX power register?

Regards

Hemabas