How to expose QSPI flash (W25Q128JVSIQ) at 0x9000 0000 over USB DFU on STM32H750VB?

[AhmedSayed]

Given that my QSPI driver and external loader for the W25Q128JVSIQ are already working, is there a hidden CubeProgrammer/DFU-descriptor trick that lets the stock USB bootloader read/write my external QSPI flash at 0x90000000, or must I build a custom USB-DFU bootloader that:

• Initializes QSPI and advertises the 0x90000000 region

• Handles read/write/erase transfers

so I can flash firmware onto the external flash over USB? If I do go the custom route, can I still use CubeProgrammer for the update, or do I need to write my own host application?

[FBL]

Hi @AhmedSayed 

STM32 built-in bootloader does not support the update of an external flash (using USB DFU or any other interface), it only supports the update of internal memory (Flash, RAM, OTP, RO, EEPROM, OB..). It should be feasible using custom bootloader to handle external flash programming.