diff --git a/src/util/vfs/vfs-mem.c b/src/util/vfs/vfs-mem.c
index 8d52eb0b1..10b03ef19 100644
--- a/src/util/vfs/vfs-mem.c
+++ b/src/util/vfs/vfs-mem.c
@@ -20,6 +20,7 @@ static void* _vfmMap(struct VFile* vf, size_t size, int flags);
 static void _vfmUnmap(struct VFile* vf, void* memory, size_t size);
 static void _vfmTruncate(struct VFile* vf, size_t size);
 static ssize_t _vfmSize(struct VFile* vf);
+static bool _vfmSync(struct VFile* vf, const void* buffer, size_t size);
 
 struct VFile* VFileFromMemory(void* mem, size_t size) {
 	if (!mem || !size) {
@@ -43,6 +44,7 @@ struct VFile* VFileFromMemory(void* mem, size_t size) {
 	vfm->d.unmap = _vfmUnmap;
 	vfm->d.truncate = _vfmTruncate;
 	vfm->d.size = _vfmSize;
+	vfm->d.sync = _vfmSync;
 
 	return &vfm->d;
 }
@@ -137,3 +139,10 @@ ssize_t _vfmSize(struct VFile* vf) {
 	struct VFileMem* vfm = (struct VFileMem*) vf;
 	return vfm->size;
 }
+
+bool _vfmSync(struct VFile* vf, const void* buffer, size_t size) {
+	UNUSED(vf);
+	UNUSED(buffer);
+	UNUSED(size);
+	return true;
+}