From Zephyr application, can not access STM32L496 register SYSCFG_MEMRMP (@0x40010000)

[poreillyNewtrax]

In order to run in system memory before jumping in STM32L496 bootloader, I need to change the value of register SYSCFG_MEMRMP (see https://www.st.com/resource/en/reference_manual/dm00083560-stm32l47xxx-stm32l48xxx-stm32l49xxx-and-stm32l4axxx-advanced-armbased-32bit-mcus-stmicroelectronics.pdf, section 9.2.1).
When I change this register with my code compiled inside STM32Cube IDE, it works properly, but when I change it from a Zephyr application, the value is not changed.
Is the default memory mapping of a STM32L496 zephyr application protecting region [0x4001000 - 0x40010400] from write access ?
Do I need to run in privileged mode to change register SYSCFG_MEMRMP ? If yes, how can I do that in Zephyr OS ?