STM32MP257F-AI3 Custom Board Not Booting from eMMC (A35 Master) After SD Image Flash

[_Krishna]

We are working on a custom board based on STM32MP257F-AI3. We flashed an X-Linux RT patched image via SD card in boot mode 0001(A35-Master), and in the ST Cube Programmer flashing completed successfully with a "download successful" pop-up in when boot mode USB/UART switches configuration is 0000.

After powering off, we set the boot switches to 0010 (eMMC boot, A35 master), but the board fails to boot properly from eMMC.

Could you please help us identify:

1. Whether the image correctly written to the eMMC boot partitions (FSBL, SSBL, U-Boot, etc.)?

2. Any mandatory post-flash steps required for enabling eMMC boot on STM32MP257?

3. The correct boot configuration (TF-A, OP-TEE, U-Boot, extlinux or boot partition flags)

Any guidance on debugging or verifying the eMMC boot flow would be helpful.

[erna23]

To boot STM32MP257 from eMMC:

1. Ensure the full image (FSBL, SSBL, TF-A, U-Boot, OP-TEE, rootfs) is flashed to eMMC.

2. Set boot switches = 0010 (A35 master).

3. Verify eMMC partitions and boot flags (extlinux/bootable).

4. Use UART console to debug early boot messages.

Common issues: missing FSBL/SSBL, wrong partition flags, or extlinux misconfiguration.

[Eldam]

Hey, 

From our side ,we boot from sdcard, we use an usb key to retreive ext4 files & tfa & uboot & so on.

i use a home made script to raw copy and "format" emmc. (see attached file) 

Attention should be made with and mmcblkXX naming :

#enable le boot de la mmc
mmc bootpart enable 2 1 /dev/mmcblk2

In order to debug, emmc should be seen when using "lsblk" even when booting from sdcard

validated with SDK 2.0

hope this help a bit

[_Krishna]

Thanks for the reply. It helps a lot I will get back to this once it is finished and I am currently testing some image related task once it is finished I will check both the solutions.

Thanks to @erna23 , @Eldam for you suggestions.


Thanks and regards,
Preetham Krishna

[PatrickF]

HI @_Krishna 

unclear what you mean by "we flashed an X-Linux RT patched image via SD card in boot mode 0001(A35-Master)".

Usually, the eMMC is flashed with CubeProgrammer using USB DFU mode (boot switches to 0000 or 1111)

Could you share the .tsv file used for the eMMC ?

https://wiki.st.com/stm32mpu/wiki/STM32CubeProgrammer_flashlayout#e-E2-80-A2MMC

Regards.

[_Krishna]

Hi @PatrickF ,

custom Yocto image for stm32mp257fai3 processor with rt patch enabled using X-LINUX-RT. The board boot switches are in order boot[3:0] = 0001 in SD-Card boot mode it is successful but with it but with EMMC mode it is unsuccessful.
I have tried flashing the image in EMMC using Cube Programmer.


Thanks and regards,
Preetham.

[PatrickF]

Hi, 

please share eMMC TSV file used for Flashload and UART console log during eMMC boot.

If no UART console output, it is likely that PH4 is toggling few Hz if FSBL fail to load (See AN5489), in that case, could you share BootROM trace dump using https://wiki.st.com/stm32mpu/wiki/STM32_MPU_ROM_trace_analyzer#On_STM32MP2_series ?

Regards.