diff --git a/cert.go b/cert.go
index dd8a1f5..0c897dd 100644
--- a/cert.go
+++ b/cert.go
@@ -82,8 +82,6 @@ func (c *CertificateDir) Lookup(scope string) (tls.Certificate, bool) {
 // localhost.crt (certificate) and localhost.key (private key).
 // New certificates will be written to this directory.
 func (c *CertificateDir) Load(path string) error {
-	c.mu.Lock()
-	defer c.mu.Unlock()
 	matches, err := filepath.Glob(filepath.Join(path, "*.crt"))
 	if err != nil {
 		return err
@@ -99,8 +97,7 @@ func (c *CertificateDir) Load(path string) error {
 		scope = strings.ReplaceAll(scope, ":", "/")
 		c.Add(scope, cert)
 	}
-	c.dir = true
-	c.path = path
+	c.SetDir(path)
 	return nil
 }
 
diff --git a/tofu.go b/tofu.go
index 9fa08eb..68f2a96 100644
--- a/tofu.go
+++ b/tofu.go
@@ -90,20 +90,12 @@ func (k *KnownHostsFile) writeKnownHost(w io.Writer, hostname string, f Fingerpr
 // It creates the file if it does not exist.
 // New known hosts will be appended to the file.
 func (k *KnownHostsFile) Load(path string) error {
-	k.mu.Lock()
-	defer k.mu.Unlock()
-	f, err := os.OpenFile(path, os.O_CREATE|os.O_RDONLY, 0644)
+	f, err := os.OpenFile(path, os.O_CREATE|os.O_RDWR, 0644)
 	if err != nil {
 		return err
 	}
 	k.Parse(f)
-	f.Close()
-	// Open the file for append-only use
-	f, err = os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0644)
-	if err != nil {
-		return err
-	}
-	k.out = f
+	k.SetOutput(f)
 	return nil
 }