Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32h5/STM32H503/FLASH/FLASH_HDP2R_CUR#0x0
FLASH HDP Bank2 register
Bank 2 HDPL barrier start set in number of 8 Kbytes sectors
Bank 2 HDPL barrier end set in number of 8 Kbytes sectors
https://github.com/modm-io/cmsis-svd-stm32