int dfu_read(struct dfu_entity *de, void *buf, int size, int blk_seq_num);
int dfu_write(struct dfu_entity *de, void *buf, int size, int blk_seq_num);
int dfu_read(struct dfu_entity *de, void *buf, int size, int blk_seq_num);
int dfu_write(struct dfu_entity *de, void *buf, int size, int blk_seq_num);