My current project is based on STM32H743IIT6 microcontroller with CMSIS RTOS v2, FATFS, USB FS as Mass Storage Host class. Recently, I upgraded to H7 firmware v1.9 after which FATFS API return "FR_DISK_ERR" error frequently.
As a workaround, I had to replace these files "stm32h7xx_ll_usb.c", "stm32h7xx_ll_usb.h", "stm32h7xx_hal_hcd.c" and "stm32h7xx_hal_hcd.h" in latest drivers in v1.9 to the once present in earlier version that is H7 firmware v1.8.
There are changes in USB link layer drivers & HCD drivers in latest firmware and that seems to be the root cause of these issue. I narrowed down at a place in USB link layer "stm32h7xx_ll_usb.c" to function like "USB_ReadPacket()", "USB_WritePacket()" where in earlier v1.8 read and write from USBx_DFIFO were 32bit word aligned which is NOT the case with latest firmware v1.9. I am not sure if word alignment is the issue here but it has something to do with this USB and HCD drivers cause replacing them with the older version in latest firmware seems to work for me.
