diff --git a/merge.go b/merge.go
index 5b68a8b..65dc03e 100644
--- a/merge.go
+++ b/merge.go
@@ -84,8 +84,8 @@ const (
 )
 
 type MergeOptions struct {
-	Version uint
-	Flags   MergeTreeFlag
+	Version     uint
+	TreeFlags   MergeTreeFlag
 
 	RenameThreshold uint
 	TargetLimit     uint
@@ -97,7 +97,7 @@ type MergeOptions struct {
 func mergeOptionsFromC(opts *C.git_merge_options) MergeOptions {
 	return MergeOptions{
 		Version:         uint(opts.version),
-		Flags:           MergeTreeFlag(opts.flags),
+		TreeFlags:           MergeTreeFlag(opts.tree_flags),
 		RenameThreshold: uint(opts.rename_threshold),
 		TargetLimit:     uint(opts.target_limit),
 		FileFavor:       MergeFileFavor(opts.file_favor),
@@ -123,7 +123,7 @@ func (mo *MergeOptions) toC() *C.git_merge_options {
 	}
 	return &C.git_merge_options{
 		version:          C.uint(mo.Version),
-		flags:            C.git_merge_tree_flag_t(mo.Flags),
+		tree_flags:       C.git_merge_tree_flag_t(mo.TreeFlags),
 		rename_threshold: C.uint(mo.RenameThreshold),
 		target_limit:     C.uint(mo.TargetLimit),
 		file_favor:       C.git_merge_file_favor_t(mo.FileFavor),
@@ -333,7 +333,7 @@ func populateCMergeFileOptions(c *C.git_merge_file_options, options MergeFileOpt
 	c.our_label = C.CString(options.OurLabel)
 	c.their_label = C.CString(options.TheirLabel)
 	c.favor = C.git_merge_file_favor_t(options.Favor)
-	c.flags = C.git_merge_file_flags_t(options.Flags)
+	c.flags = C.uint(options.Flags)
 }
 
 func freeCMergeFileOptions(c *C.git_merge_file_options) {
diff --git a/repository.go b/repository.go
index b65867b..9917c60 100644
--- a/repository.go
+++ b/repository.go
@@ -616,16 +616,19 @@ func (v *Repository) RemoveNote(ref string, author, committer *Signature, id *Oi
 
 // DefaultNoteRef returns the default notes reference for a repository
 func (v *Repository) DefaultNoteRef() (string, error) {
-	var ptr *C.char
+	buf := C.git_buf{}
 
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	if ret := C.git_note_default_ref(&ptr, v.ptr); ret < 0 {
+	if ret := C.git_note_default_ref(&buf, v.ptr); ret < 0 {
 		return "", MakeGitError(ret)
 	}
 
-	return C.GoString(ptr), nil
+	ret := C.GoString(buf.ptr)
+	C.git_buf_free(&buf)
+
+	return ret, nil
 }
 
 type RepositoryState int
diff --git a/vendor/libgit2 b/vendor/libgit2
index d675982..4c02d39 160000
--- a/vendor/libgit2
+++ b/vendor/libgit2
@@ -1 +1 @@
-Subproject commit d675982a15388d8c413acda139b4662062cf3286
+Subproject commit 4c02d393748d0db382450871ad9ef6898a2ce360