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Visitor II
Nov 24, 2025 6:16 AM UTC
Solved

Flashing Zephyr Application to External Flash on Nucleo-H7S3L8

 

I am working with Zephyr RTOS on the Nucleo-H7S3L8 board and have successfully flashed and run the blinky example on internal flash.

However, I noticed that Zephyr does not provide official documentation for flashing applications into external flash.

My question:

  • Does Zephyr offer any official method or west command to flash applications directly into external flash, similar to how west flash works for internal flash?
Erwan Gouriou
Erwan GouriouBest answer
ST Employee
Nov 28, 2025 8:02 AM UTC

Please follow up on https://github.com/zephyrproject-rtos/zephyr/pull/99647

This will introduce support of building and flashing of application on external flash using MCUBoot as bootloader, similarly to what is supported on DK Board (see https://docs.zephyrproject.org/latest/boards/st/stm32h7s78_dk/doc/index.html#application-in-external-flash)

 

3 replies

ST Technical Moderator
Nov 25, 2025 1:25 PM UTC

Hello @laya 

STM32CubeProgrammer is setup as the default west runner for STM32 boards supported by Zephyr. For your case you can use STM32cubeProgrammer GUI instead of west commande to flash the code in external memory. 

In order to give better visibility on the answered topics, please click on 'Best answer' on the reply which solved your issue or answered your question. Saket_Om
ST Employee
Nov 25, 2025 2:21 PM UTC

Hello @laya,

I suggest that you program the external memory from the internal flash. So, you will XIP from external memory, then jump to internal flash in order to program the external memory then jump back to XIP.

I hope my answer has been helpful. When your question is resolved, please mark this topic as the solution. This will help others find the answer more quickly.

Thank you for your contribution.

Best regards,
Dor_RH

 

 

In order to give better visibility on the answered topics, please click on 'Best answer' on the reply which solved your issue or answered your question. Dor_RH
Erwan Gouriou
Erwan GouriouBest answer
ST Employee
Nov 28, 2025 8:02 AM UTC

Please follow up on https://github.com/zephyrproject-rtos/zephyr/pull/99647

This will introduce support of building and flashing of application on external flash using MCUBoot as bootloader, similarly to what is supported on DK Board (see https://docs.zephyrproject.org/latest/boards/st/stm32h7s78_dk/doc/index.html#application-in-external-flash)