SD Card over SPI, FSMediaError on Mount

Hello folks, my first time posting on this forum so apologies if I am missing any information in this post.

I am using a STM32F746NHGx with MDK-Pro. The hardware I am working with has an 8GB SD card connected over SPI that I'm told has "never worked". I was hoping to change that but I'm unsuccessful so far.

I have found and fixed few configuration issues that may be contributing to the problem, and I've gone through the demo FileSystemComponent application, but I still get an FsMediaError when I call the fmount or fformat operations. The finit operation returns fsOK.

Here is my configuration for FS_Config_MC_0.h

#define MC0_ENABLE  1
#define MC0_MCI_DRIVER  0
#define MC0_SPI_DRIVER  2
#define MC0_SPI 1
#define MC0_CACHE_SIZE  4
#define MC0_CACHE_RELOC 0
#define MC0_CACHE_ADDR  0x7FD00000
#define MC0_NAME_CACHE_SIZE 0
#define MC0_FAT_JOURNAL 0

And what I believe are the relevant portions of RTE_Device.h (I've verified the pins match on the PCB with the correct SD card components)

#define RTE_SPI2    1
#define RTE_SPI2_MISO_PORT_ID   3
#define RTE_SPI2_MOSI_PORT_ID   4
#define RTE_SPI2_SCL_PORT_ID    3
#define RTE_SPI2_NSS_PORT_ID    4
#define RTE_SPI2_RX_DMA 0
#define RTE_SPI2_TX_DMA 0

#define RTE_SDMMC1  0

Finally, the other possibly relevant setting I have found is in FS_Config.c

#define FS_INITIAL_CDRIVE   2

My main.c (abbreviated below) is pretty simple:

#define SD_FILESYS_DRIVE    "M0"

int main(void)
{
    MPU_Config();
    CPU_CACHE_Enable();
    osKernelInitialize();
    errorMutexId = osMutexCreate(osMutex(errorMutex));
    HAL_Init();
    BSP_ClocksInit();
	PeriphClock_Config();
	digIOInit();
	Init_Power_Reset();
	MX_RTC_Init();
	BSP_SDRAM_Init();
	init_I2C();
	framInit();
	initNORFilesystem();
	initSDFilesystem();
}

int initSDFilesystem(void)
    fsStatus SDStatus;
    SDStatus=finit(SD_FILESYS_DRIVE);
    	if (SDStatus != fsOK)
	    {
	    	printf("SD init Failed\n");
    		return SD_INIT_FAILED;
    	}
	
    SDStatus=fformat(SD_FILESYS_DRIVE, NULL);
    if (SDStatus != fsOK)
    {
    	printf("SD init Failed\n");
    	return SD_INIT_FAILED;
    }
}

All I'm hoping for is a suggestion of a configuration option I may have overlooked or some suggestions for next steps in debugging this issue. Other possibly relevant notes:

1. I'm using SPI1 successfully for other operations.

2. I can read and write successfully to the NOR flash.

3. There are no other components on the SPI bus.

4. I've tried formatting the filesystem as fat32 using a PC and then just calling fmount, but no luck.

Any advice would be greatly appreciated!

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