Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32wb0/STM32WB05/RADIO_REG_REG/AA1_DIG_USR#0x0
AA1_DIG_USR register
Next byte of the Bluetooth LE Access Address code.
https://github.com/modm-io/cmsis-svd-stm32