diff --git a/lib/app/app.cpp b/lib/app/app.cpp
index e2a9826..f4885c9 100644
--- a/lib/app/app.cpp
+++ b/lib/app/app.cpp
@@ -198,7 +198,6 @@ void setupApiSettings()
 		root["system"]["dst"] = NVS.getInt("system.dst");
 		root["system"]["wifi"] = NVS.getString("wifi.ssid");
 
-		//root["device"]["angle"] = NVS.getInt("device.angle");
 		root["device"]["theme"] = NVS.getString("device.theme");
 		root["device"]["name"] = NVS.getString("device.name");
 
@@ -455,15 +454,16 @@ void setupApiCache()
 }
 
 /**
- * api data endpoint
+ * ota update
  */
 void setupOTA()
 {
-	// Simple Firmware Update Form
+	// recovery update mode
 	server.on("/update", HTTP_GET, [](AsyncWebServerRequest *request) {
 		request->send(200, "text/html", "<form method='POST' action='/update' enctype='multipart/form-data'><input type='file' name='update'><input type='submit' value='Update'></form>");
 	});
 
+	// handle update
 	server.on(
 		"/update", HTTP_POST, [](AsyncWebServerRequest *request) {},
 		[](AsyncWebServerRequest *request, String filename, size_t index, uint8_t *data, size_t len, bool final) {
diff --git a/lib/download/download.cpp b/lib/download/download.cpp
index a8a366f..e7ffb4c 100644
--- a/lib/download/download.cpp
+++ b/lib/download/download.cpp
@@ -4,7 +4,7 @@
 #include "device.h"
 #include "esp_task_wdt.h"
 
-bool downloadFile(String url, const char *path, const char* CAcert)
+bool downloadFile(String url, const char *path, const char *CAcert)
 {
 	// @note duration time: 200kb = 35sec write to flash
 	Serial.println("Download file: " + url);
@@ -32,9 +32,12 @@ bool downloadFile(String url, const char *path, const char* CAcert)
 	// use the last 8 bytes of the unique serial id
 	http.addHeader("X-PaperDash-Id", DeviceId);
 
-	if (CAcert) {
+	if (CAcert)
+	{
 		http.begin(url, CAcert);
-	} else {
+	}
+	else
+	{
 		http.begin(url);
 	}
 
@@ -68,7 +71,6 @@ bool downloadFile(String url, const char *path, const char* CAcert)
 	return !hasError;
 }
 
-
 bool downloadFile(String url, const char *path)
 {
 	return downloadFile(url, path, NULL);