diff --git a/drivers/fwu-mdata/fwu-mdata-uclass.c b/drivers/fwu-mdata/fwu-mdata-uclass.c
index 0a8edaaa41..145479bab0 100644
--- a/drivers/fwu-mdata/fwu-mdata-uclass.c
+++ b/drivers/fwu-mdata/fwu-mdata-uclass.c
@@ -20,7 +20,8 @@
  *
  * Return: 0 if OK, -ve on error
  */
-int fwu_read_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary)
+int fwu_read_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary,
+		   uint32_t size)
 {
 	const struct fwu_mdata_ops *ops = device_get_ops(dev);
 
@@ -29,7 +30,7 @@ int fwu_read_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary)
 		return -ENOSYS;
 	}
 
-	return ops->read_mdata(dev, mdata, primary);
+	return ops->read_mdata(dev, mdata, primary, size);
 }
 
 /**
@@ -37,7 +38,8 @@ int fwu_read_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary)
  *
  * Return: 0 if OK, -ve on error
  */
-int fwu_write_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary)
+int fwu_write_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary,
+		    uint32_t size)
 {
 	const struct fwu_mdata_ops *ops = device_get_ops(dev);
 
@@ -46,7 +48,7 @@ int fwu_write_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary)
 		return -ENOSYS;
 	}
 
-	return ops->write_mdata(dev, mdata, primary);
+	return ops->write_mdata(dev, mdata, primary, size);
 }
 
 UCLASS_DRIVER(fwu_mdata) = {
diff --git a/drivers/fwu-mdata/gpt_blk.c b/drivers/fwu-mdata/gpt_blk.c
index c7284916c4..97eac3611f 100644
--- a/drivers/fwu-mdata/gpt_blk.c
+++ b/drivers/fwu-mdata/gpt_blk.c
@@ -81,15 +81,14 @@ static int gpt_get_mdata_disk_part(struct blk_desc *desc,
 	return -ENOENT;
 }
 
-static int gpt_read_write_mdata(struct blk_desc *desc,
-				struct fwu_mdata *mdata,
-				u8 access, u32 part_num)
+static int gpt_read_write_mdata(struct blk_desc *desc, struct fwu_mdata *mdata,
+				u8 access, u32 part_num, u32 size)
 {
 	int ret;
 	u32 len, blk_start, blkcnt;
 	struct disk_partition info;
 
-	ALLOC_CACHE_ALIGN_BUFFER_PAD(struct fwu_mdata, mdata_aligned, 1,
+	ALLOC_CACHE_ALIGN_BUFFER_PAD(u8, mdata_aligned, size,
 				     desc->blksz);
 
 	if (!mdata)
@@ -101,7 +100,7 @@ static int gpt_read_write_mdata(struct blk_desc *desc,
 		return -ENOENT;
 	}
 
-	len = sizeof(*mdata);
+	len = size;
 	blkcnt = BLOCK_CNT(len, desc);
 	if (blkcnt > info.size) {
 		log_debug("Block count exceeds FWU metadata partition size\n");
@@ -114,7 +113,7 @@ static int gpt_read_write_mdata(struct blk_desc *desc,
 			log_debug("Error reading FWU metadata from the device\n");
 			return -EIO;
 		}
-		memcpy(mdata, mdata_aligned, sizeof(struct fwu_mdata));
+		memcpy(mdata, mdata_aligned, size);
 	} else {
 		if (blk_dwrite(desc, blk_start, blkcnt, mdata) != blkcnt) {
 			log_debug("Error writing FWU metadata to the device\n");
@@ -164,7 +163,7 @@ static int fwu_mdata_gpt_blk_probe(struct udevice *dev)
 }
 
 static int fwu_gpt_read_mdata(struct udevice *dev, struct fwu_mdata *mdata,
-			      bool primary)
+			      bool primary, u32 size)
 {
 	struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
 	struct blk_desc *desc = dev_get_uclass_plat(priv->blk_dev);
@@ -177,11 +176,13 @@ static int fwu_gpt_read_mdata(struct udevice *dev, struct fwu_mdata *mdata,
 	}
 
 	return gpt_read_write_mdata(desc, mdata, MDATA_READ,
-				    primary ? g_mdata_part[0] : g_mdata_part[1]);
+				    primary ?
+				    g_mdata_part[0] : g_mdata_part[1],
+				    size);
 }
 
 static int fwu_gpt_write_mdata(struct udevice *dev, struct fwu_mdata *mdata,
-			       bool primary)
+			       bool primary, u32 size)
 {
 	struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
 	struct blk_desc *desc = dev_get_uclass_plat(priv->blk_dev);
@@ -194,7 +195,9 @@ static int fwu_gpt_write_mdata(struct udevice *dev, struct fwu_mdata *mdata,
 	}
 
 	return gpt_read_write_mdata(desc, mdata, MDATA_WRITE,
-				    primary ? g_mdata_part[0] : g_mdata_part[1]);
+				    primary ?
+				    g_mdata_part[0] : g_mdata_part[1],
+				    size);
 }
 
 static const struct fwu_mdata_ops fwu_gpt_blk_ops = {
diff --git a/drivers/fwu-mdata/raw_mtd.c b/drivers/fwu-mdata/raw_mtd.c
index 17e4517973..9f3f1dc213 100644
--- a/drivers/fwu-mdata/raw_mtd.c
+++ b/drivers/fwu-mdata/raw_mtd.c
@@ -97,22 +97,24 @@ lock:
 	return ret;
 }
 
-static int fwu_mtd_read_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary)
+static int fwu_mtd_read_mdata(struct udevice *dev, struct fwu_mdata *mdata,
+			      bool primary, u32 size)
 {
 	struct fwu_mdata_mtd_priv *mtd_priv = dev_get_priv(dev);
 	struct mtd_info *mtd = mtd_priv->mtd;
 	u32 offs = primary ? mtd_priv->pri_offset : mtd_priv->sec_offset;
 
-	return mtd_io_data(mtd, offs, sizeof(struct fwu_mdata), mdata, FWU_MTD_READ);
+	return mtd_io_data(mtd, offs, size, mdata, FWU_MTD_READ);
 }
 
-static int fwu_mtd_write_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary)
+static int fwu_mtd_write_mdata(struct udevice *dev, struct fwu_mdata *mdata,
+			       bool primary, u32 size)
 {
 	struct fwu_mdata_mtd_priv *mtd_priv = dev_get_priv(dev);
 	struct mtd_info *mtd = mtd_priv->mtd;
 	u32 offs = primary ? mtd_priv->pri_offset : mtd_priv->sec_offset;
 
-	return mtd_io_data(mtd, offs, sizeof(struct fwu_mdata), mdata, FWU_MTD_WRITE);
+	return mtd_io_data(mtd, offs, size, mdata, FWU_MTD_WRITE);
 }
 
 static int flash_partition_offset(struct udevice *dev, const char *part_name, fdt_addr_t *offset)
diff --git a/include/fwu.h b/include/fwu.h
index eb5638f4f3..1815bd0064 100644
--- a/include/fwu.h
+++ b/include/fwu.h
@@ -32,20 +32,24 @@ struct fwu_mdata_ops {
 	 * @dev: FWU metadata device
 	 * @mdata: Output FWU mdata read
 	 * @primary: If primary or secondary copy of metadata is to be read
+	 * @size: Size in bytes of the metadata to be read
 	 *
 	 * Return: 0 if OK, -ve on error
 	 */
-	int (*read_mdata)(struct udevice *dev, struct fwu_mdata *mdata, bool primary);
+	int (*read_mdata)(struct udevice *dev, struct fwu_mdata *mdata,
+			  bool primary, uint32_t size);
 
 	/**
 	 * write_mdata() - Write the given FWU metadata copy
 	 * @dev: FWU metadata device
 	 * @mdata: Copy of the FWU metadata to write
 	 * @primary: If primary or secondary copy of metadata is to be written
+	 * @size: Size in bytes of the metadata to be written
 	 *
 	 * Return: 0 if OK, -ve on error
 	 */
-	int (*write_mdata)(struct udevice *dev, struct fwu_mdata *mdata, bool primary);
+	int (*write_mdata)(struct udevice *dev, struct fwu_mdata *mdata,
+			   bool primary, uint32_t size);
 };
 
 #define FWU_MDATA_VERSION	0x1
@@ -80,12 +84,14 @@ struct fwu_mdata_ops {
 /**
  * fwu_read_mdata() - Wrapper around fwu_mdata_ops.read_mdata()
  */
-int fwu_read_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary);
+int fwu_read_mdata(struct udevice *dev, struct fwu_mdata *mdata,
+		   bool primary, uint32_t size);
 
 /**
  * fwu_write_mdata() - Wrapper around fwu_mdata_ops.write_mdata()
  */
-int fwu_write_mdata(struct udevice *dev, struct fwu_mdata *mdata, bool primary);
+int fwu_write_mdata(struct udevice *dev, struct fwu_mdata *mdata,
+		    bool primary, uint32_t size);
 
 /**
  * fwu_get_mdata() - Read, verify and return the FWU metadata
