int write_bootdata(unsigned char* buf, int len,unsigned int boot_volume)
{
    (void) boot_volume;
    struct boot_data_t *boot_data = NULL;
    int ret = 0;
    unsigned int i;
    unsigned int magic[2] = {BOOT_DATA_MAGIC0, BOOT_DATA_MAGIC1};
    if (len < BOOT_DATA_SEARCH_SIZE)
        ret = EKEY_NOT_FOUND;

    if (ret == 0)
    {
        /* search for boot data header prior to this offset */
        for(i = 0;i <= (BOOT_DATA_SEARCH_SIZE - sizeof(struct boot_data_t));i++)
        {
            if ( memcmp ( &buf[i], &magic[0], sizeof(magic) ) == 0)
            {
                boot_data = (struct boot_data_t*) &buf[i];
                boot_data->boot_volume = 0x52622300 | boot_volume;
                boot_data->crc = magic[0] ^ magic[1] ^ boot_data->boot_volume ^ len;
                break;
            }
        }
        if (boot_data == NULL)
            ret = EKEY_NOT_FOUND;

    }

    return ret;
}