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AN5056 Porting X-CUBE-SBSFU onto another board
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UserApp must be configured to run in the active slot (Slot active start address with
SFU_IMG_IMAGE_OFFSET) as illustrated in Figure 12 where SFU_IMG_IMAGE_OFFSET is
512 bytes for the STM32L4 Series.
Figure 12. UserApp specific linker file (NUCLEO-L476RG example)
1. Depends on the STM32 microcontroller Series.
3.2.4 Multiple image configuration
Up to three active slots (SFU_NB_MAX_ACTIVE_IMAGE) and three download slots
(SFU_NB_MAX_DWL_AREA) can be configured.
During the installation process, the active slot is identified with the SFU magic tag inside the
firmware image header (SFU1, SFU2, or SFU3). Depending on firmware compatibility
constraints, if the simultaneous firmware installation is not required, a single download slot
can be configured for the three active slots to optimize the memory footprint.
At boot, after verification of the authenticity and integrity of all firmware images, SBSFU
jumps into the active firmware image located inside the MASTER_SLOT in priority.
As a constraint, all the headers must be grouped in a single area to be protected inside the
isolated environment. Each header must be located in its own Flash memory sector.
Figure 13 shows the example of the multiple-image configuration provided in
2_Images_ExtFlash of the B-L475E-IOT01A board.
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