Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32wb/STM32WB10_CM4/Flash/ECCR#0x0
Flash ECC register
ECC fail address
System Flash ECC fail
ECC correction interrupt enable
CPU identification
ECC correction
ECC detection
https://github.com/modm-io/cmsis-svd-stm32