2025-11-05 5:53 AM
Hi,
I am working with the SBSFU_Boot on the STM32U5A9 chip. After the SBSFU_Loader has written the update image into internal memory, a reset happens in order for the SBSFU_Boot to write the image to be booted. When performing the update, it ends up in a process where it has to do some encryption. The SAES engine is initialized successfully, and then AES_Encrypt is called. This keeps on failing because a read error is reported in the SAES->SR reports a read error upon enabling the SAES peripheral.
It should be noted that the initialization and encryption sequence is strictly followed per instructions in RM0456 Rev 6 sections 50.4.4 (Initialization of SAES) and 50.4.8 (ECB/CBC encryption sequence) respectively.
What am I missing?