Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32f4/STM32F412/FLASH/CR#0x0
Control register
Programming
Sector Erase
Mass Erase
Sector number
Program size
Start
End of operation interrupt enable
Error interrupt enable
Lock
https://github.com/modm-io/cmsis-svd-stm32