Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32h5/STM32H533/OTFDEC/OTFDEC_R4KEYR0#0x0
OTFDEC region 4 key register 0
Region key, bits [31:0]
https://github.com/modm-io/cmsis-svd-stm32