Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32h7/STM32H7B0/OTFDEC1/R2NONCER0#0x0
OTFDEC region x nonce register 0
REGx_NONCE
https://github.com/modm-io/cmsis-svd-stm32