diff --git a/drivers/dfu/dfu_nand.c b/drivers/dfu/dfu_nand.c
index 97cd608..ed4ceb7 100644
--- a/drivers/dfu/dfu_nand.c
+++ b/drivers/dfu/dfu_nand.c
@@ -114,9 +114,11 @@
 	return ret;
 }
 
-long dfu_get_medium_size_nand(struct dfu_entity *dfu)
+int dfu_get_medium_size_nand(struct dfu_entity *dfu, long *size)
 {
-	return dfu->data.nand.size;
+	*size = dfu->data.nand.size;
+
+	return 0;
 }
 
 static int dfu_read_medium_nand(struct dfu_entity *dfu, u64 offset, void *buf,