diff --git a/README.md b/README.md
index 792b4d3..99f9e59 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 # Buzzer
 ## Build
 ```shell
-platformio run --target uploadfs --environment wemos_d1_mini32
+platformio run --target uploadfs
 platformio run --target upload
 ```
 
diff --git a/src/main.cpp b/src/main.cpp
index 32ba5bf..97be26d 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -110,6 +110,8 @@ void setup()
   server.on("/play", HTTP_GET, onPlay);
   server.on("/available-files", HTTP_GET, onAvailableFiles);
   server.on("/select-file", HTTP_POST, onSelectFile);
+  server.onNotFound([](AsyncWebServerRequest *request)
+                    { request->send(404); });
   server.serveStatic("/", SPIFFS, "/www/").setDefaultFile("index.html");
   server.begin();