STMicroelectronics/STM32CubeU5

SBSFU

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Hello,

I have a small question about how the SBSFU example works. Does it work in the secure zone or in the non secure zone? If it works in the non secure zone, how can I make it work in the secure zone?

Thanks in advance

@aitor4321 It works in both zones. Recently I was puzzled as well so I visualized it in Excel. See below, green is Trust Zone.

image

Hello @tdjastrzebski,

Thank you for responding. So, if I modify the main file of SBSFU_APPLI_SECURE and make an application that saves data in memory, will it save it in the secure zone? If someone tries to retrieve that data, could they access that memory?

@aitor4321 In general, app in secure zone has access to non-secure zone memory, including flash, but not the other way around. See AN5347. Where data is saved is up to you. Note that this implementation contains two DATA images - secure and non-secure, each has two slots (primary and secondary). More details you can find in MCUboot docs. I suggest starting there.

ST Internal Reference: 179481

Hi,

@tdjastrzebski, thank you for your contribution.

@aitor4321, did the indications provided by @tdjastrzebski help you with what you are trying to do? In the meanwhile, your question has been forwarded to our development teams. I will keep you informed.

With regards,

With regards,

Hi @ALABSTM,

Yes, the instructions provided by @tdjastrzebski have helped me with what I'm trying to accomplish. Thank you!

Looking forward to hearing from the development teams.

With regards,

Hi @aitor4321,

Back to you with an extra information from our development teams. You asked:

If someone tries to retrieve that data, could they access that memory?

The answer is that it depends on the location where the modified SBSFU_Appli_Secure application saves data... If it save it to a non-secure or to a secure area in the flash memory. Hence, you have to ensure that your data is saved to a secure area in the flash memory.

I hope this helps. Please allow me to close this thread.

With regards,