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Associate III
July 10, 2025
Solved

Review a secret file content for STM32MP2 series to enable secure boot

  • July 10, 2025
  • 1 reply
  • 521 views

My goal is to create a SSP payload and write it to the OTP of the STM32MP257F chip. The OS running on my KIT is based on OpenSTLinux.

To get the SSP Payload, a Secret file is required. I just need secure boot.

I refer to the following sources:

The contents of my Secret file will include the components as shown below. (Json file attached)

ThinhNguyen_0-1752114013070.png

Is a secret file with such components enough for secure boot? And please advise if there are any invalid options in the Secret list

Best answer by ThomasB

Hello @ThinhNguyen,

On MP2x A35TD these four elements are sufficient.

Keep in mind that the first two elements (OEM_KEY1_ROT and RMA_LOCK_PSWD) are mandatory. The two others are optional, depending on what you want to achieve :

  • OEM_FIP_EDMK is used to decrypt the FIP binaries (OP-TEE, U-Boot). If you do not encrypt your FIP, it is not required.
  • OEM_KEY1_EDMK is used to decrypt the FSBL (TF-A). If you do not encrypt the FSBL, it is not required.

 

Best regards,

Thomas

1 reply

ThomasBBest answer
Technical Moderator
August 11, 2025

Hello @ThinhNguyen,

On MP2x A35TD these four elements are sufficient.

Keep in mind that the first two elements (OEM_KEY1_ROT and RMA_LOCK_PSWD) are mandatory. The two others are optional, depending on what you want to achieve :

  • OEM_FIP_EDMK is used to decrypt the FIP binaries (OP-TEE, U-Boot). If you do not encrypt your FIP, it is not required.
  • OEM_KEY1_EDMK is used to decrypt the FSBL (TF-A). If you do not encrypt the FSBL, it is not required.

 

Best regards,

Thomas

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