STM32H7RS: How to safely update bootloader from appli?

[h p]

When the bootloader is updated from the main appli, the start address at reset can be set to the start address of the main application. By this, it is assured that the device can still be started if the bootloader update could not be completed, e.g. bootloader flash erased but not completely written.

On STM32F4 the start address at reset can be set by register FLASH_NSBOOTADD0R.

But on the STM32H7R the start address register is only read-only, Reference Manual 8.5.1 is all 'r' at:

SBS boot status register (SBS_BOOTSR), INITVTOR[31:0]: initial vector for Cortex-M7 (This register includes the physical boot address used by the Cortex-M7 after reset).

Can the bootloader be safely updated by other means?

Thanks in advance for any advice.