diff --git a/utils.c b/utils.c
index 74d2c597..46b9a2c0 100644
--- a/utils.c
+++ b/utils.c
@@ -212,6 +212,8 @@ int make_btrfs(int fd, const char *device, const char *label,
 	BUG_ON(ret != leafsize);
 
 	/* create the items for the extent tree */
+	memset(buf->data+sizeof(struct btrfs_header), 0,
+		leafsize-sizeof(struct btrfs_header));
 	nritems = 0;
 	itemoff = __BTRFS_LEAF_DATA_SIZE(leafsize);
 	for (i = 1; i < 7; i++) {
@@ -257,6 +259,8 @@ int make_btrfs(int fd, const char *device, const char *label,
 	BUG_ON(ret != leafsize);
 
 	/* create the chunk tree */
+	memset(buf->data+sizeof(struct btrfs_header), 0,
+		leafsize-sizeof(struct btrfs_header));
 	nritems = 0;
 	item_size = sizeof(*dev_item);
 	itemoff = __BTRFS_LEAF_DATA_SIZE(leafsize) - item_size;
@@ -338,6 +342,8 @@ int make_btrfs(int fd, const char *device, const char *label,
 	ret = pwrite(fd, buf->data, leafsize, blocks[3]);
 
 	/* create the device tree */
+	memset(buf->data+sizeof(struct btrfs_header), 0,
+		leafsize-sizeof(struct btrfs_header));
 	nritems = 0;
 	itemoff = __BTRFS_LEAF_DATA_SIZE(leafsize) -
 		sizeof(struct btrfs_dev_extent);
@@ -371,6 +377,8 @@ int make_btrfs(int fd, const char *device, const char *label,
 	ret = pwrite(fd, buf->data, leafsize, blocks[4]);
 
 	/* create the FS root */
+	memset(buf->data+sizeof(struct btrfs_header), 0,
+		leafsize-sizeof(struct btrfs_header));
 	btrfs_set_header_bytenr(buf, blocks[5]);
 	btrfs_set_header_owner(buf, BTRFS_FS_TREE_OBJECTID);
 	btrfs_set_header_nritems(buf, 0);
@@ -379,6 +387,8 @@ int make_btrfs(int fd, const char *device, const char *label,
 	BUG_ON(ret != leafsize);
 
 	/* finally create the csum root */
+	memset(buf->data+sizeof(struct btrfs_header), 0,
+		leafsize-sizeof(struct btrfs_header));
 	btrfs_set_header_bytenr(buf, blocks[6]);
 	btrfs_set_header_owner(buf, BTRFS_CSUM_TREE_OBJECTID);
 	btrfs_set_header_nritems(buf, 0);