Hardfault writing struct to STM32H7 flash using STM32 HAL Driver

[gcoard]

I'm trying to write a struct of size around 680 bytes to Sector 1, Bank 2 of the flash in an STM32H757XIH6. I'm pretty new to this kind of thing so I'm slowly building on the code. I'm using the STM32 HAL driver. The address of this sector is 0x08100000.

Here's the code:

typedef struct {
    uint32_t data_header;
    Parameter parameter[NUMBER_PARAMETERS];
    int screen_paras[MAX_SCREENS][MAX_WIDGETS];
} Persistent_data;


void save_data() {
    Persistent_data save_data;

    uint32_t data_header = DATA_HEADER;

    save_data.data_header = data_header;
    memcpy(save_data.parameter, parameter, sizeof(save_data.parameter));
    memcpy(save_data.screen_paras, screen_paras, sizeof(save_data.screen_paras));

    size_t size = sizeof(Persistent_data);
    uint32_t word_count = (size + 3) / 4; //32bit alignment
    Flash_Write(FLASH_START_ADDRESS, (uint32_t*)&save_data, word_count);
    }


HAL_StatusTypeDef Flash_Write(uint32_t address, uint32_t* data, uint32_t length) {
    HAL_StatusTypeDef status = HAL_OK;

    // Ensure address is within the flash range
    if (address < FLASH_USER_START_ADDR || (address + length) > FLASH_USER_END_ADDR) {
        return HAL_ERROR;
        }

    // Unlock the Flash
    HAL_FLASH_Unlock();

    // Erase the flash sector
    FLASH_EraseInitTypeDef eraseInitStruct = {
        .TypeErase = FLASH_TYPEERASE_SECTORS,
        .Banks = FLASH_BANK_2,
        .Sector = FLASH_SECTOR_1,
        .NbSectors = 1,
        .VoltageRange = FLASH_VOLTAGE_RANGE_3,
        };
    uint32_t sectorError = 0;

    status = HAL_FLASHEx_Erase(&eraseInitStruct, &sectorError);
    if (status != HAL_OK) {
        HAL_FLASH_Lock();
        return status;
        }

    // Write the data
     for (int i = 0; i < length / 4; i++) { // Writing 32-bit words
        status = HAL_FLASH_Program(FLASH_TYPEPROGRAM_FLASHWORD, address, data[i]);
        if (status != HAL_OK) {
            break;
            }
        address += 4; // Increment address by 4 bytes (32 bits)
        }

    // Lock the Flash
    HAL_FLASH_Lock();
    return status;
    }

When I try to save the save_data (with all it's members) a hard fault is generated from the line 

status = HAL_FLASH_Program(FLASH_TYPEPROGRAM_FLASHWORD, address, data[i]);

Tracing it further it gets to *dest_addr = *src_addr; in stm32h7xx_hal_flash.c. From there I'm not sure how to interpret the crash stack, next is <signal handler called>() at 0xffffffed 

ffffffed:   Failed to execute MI command:
          -data-disassemble -s 4294967277 -e 4294967529 -- 3
          Error message from debugger back end:
          Cannot access memory at address 0xffffffec

Please let me know if I can provide any more info