How to make TFA redundant and how to make ROM code select different partitions of FSBL?

ZUl A.1 · ‎2023-03-16

In stm32mp157, I need two partitions for FSBL, and it is working correctly, but I want to make TFA redundant meaning I should be able to update the second partition of FSBL and then shift it on the second partition on restart.

I have made roofs redundant, but then I used environment variables inside U-BOOT to switch partitions. TFA (BL2) runs instantly after the ROM code, and I cannot change that.

Is there any solution that I can do here? What is the purpose of having two FSBL partitions if it is not for redundant TFA?

ZUl A.1 · ‎2023-03-22

https://wiki.st.com/stm32mpu/wiki/STM32CubeProgrammer_flashlayout

Also, you have suggested that there should be two partitions for TFA, FSBL1 and FSBL2.

I have corrupted the FSBL1 with random numbers but it does not go to FSBL2.

Olivier GALLIEN · ‎2023-03-24

Hi @ZUl A.1 ,

What kind of flash memory are you using?

Olivier

Olivier GALLIEN
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ZUl A.1 · ‎2023-03-24

I am using eMMC. I am then using DD to corrupt the memory with some random number or zeros but when I restart, it just does not go the FSBL2 (partition 2).

Olivier GALLIEN · ‎2023-03-27

Hi @ZUl A.1 ,

My apology, for eMMC there's no mechanism of fallback in case of corruption..

There's only one "active" boot partition seen by the ROMCODE as per describe in

https://wiki.st.com/stm32mpu/wiki/STM32_MPU_ROM_code_overview#Boot_from_e-E2-80-A2MMC-E2-84-A2

you can change it by SW :

https://wiki.st.com/stm32mpu/wiki/How_to_manually_update_bootloaders#Select_boot_partition

Olivier

Olivier GALLIEN
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