diff --git a/README.md b/README.md
index 3481056..192a252 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,16 @@
 
 The HannaBox is a Wifi enabled music player for toddlers and small children. It features an sd card reader, three buttons, a speaker up to 3 watts and an RFID reader. It is powered by a ESP32 microcontroller module.
 
+## Preparation
+
+The library https://github.com/schreibfaul1/ESP32-audioI2S is not available for Platformio in a working version. It is linked into the `lib` folder as a git submodule. 
+
+Init and pull the submodule before continuing:
+
+```
+git submodule update --init
+```
+
 ## Microcontroller
 
 We are using an ESP-WROOM-32 module. For the mp3 decoding we need a multicore CPU, be careful, there are some ESP32 with only one core.
diff --git a/src/main.cpp b/src/main.cpp
index e0de7b3..9f946c7 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -90,6 +90,10 @@ bool asyncNext = false;
 
 bool asyncPrev = false;
 
+bool SDActive = false;
+
+bool RFIDActive = false;
+
 uint16_t voltage_threshold_counter = 0;
 
 size_t free_heap = 0;
@@ -102,22 +106,35 @@ std::map<String, String> rfid_map{{"67 152 204 14", "01-The_Box_Tops-The_Letter.
 
 void activateSD()
 {
+  if (SDActive)
+    return;
   digitalWrite(CS_SDCARD, LOW);
+  if (!SD.begin(CS_SDCARD))
+  {
+    Serial.println("SD initialization failed!");
+    while (1)
+      ;
+  }
+  SDActive = true;
 }
 
 void deactivateSD()
 {
+  //SD.end();
   digitalWrite(CS_SDCARD, HIGH);
+  SDActive = false;
 }
 
 void activateRFID()
 {
   digitalWrite(CS_RFID, LOW);
+  RFIDActive = true;
 }
 
 void deactivateRFID()
 {
   digitalWrite(CS_RFID, HIGH);
+  RFIDActive = false;
 }
 
 // Make size of files human readable
@@ -508,25 +525,24 @@ void setup()
   pinMode(CS_SDCARD, OUTPUT);
 
   deactivateRFID();
+
+
+  Serial.print("Initializing SD card...");
   activateSD();
+  Serial.println("SD initialization done.");
+  
 
   //deep sleep wakeup
   esp_sleep_enable_ext0_wakeup((gpio_num_t)BTN_START_STOP, LOW);
 
-  Serial.print("Initializing SD card...");
 
-  if (!SD.begin(CS_SDCARD))
-  {
-    Serial.println("SD initialization failed!");
-    while (1)
-      ;
-  }
-  Serial.println("SD initialization done.");
 
   rootNode.buildDirectoryTree("/");
   rootNode.printDirectoryTree();
 
   readDataFromFile(mapping_file.c_str());
+
+  
   
   String progressPath = "/"+sys_dir+"/"+progress_file;
 
@@ -710,6 +726,9 @@ String getStartupSoundDir() {
 
 void loop()
 {
+  deactivateRFID();
+  activateSD();
+
   if (audio.isRunning())
   {
     if (asyncStop)
@@ -717,8 +736,6 @@ void loop()
       asyncStop = false;
       stop();
     }
-    deactivateRFID();
-    activateSD();
     audio.loop();
     if (currentNode != nullptr && !prepareSleepMode)
     {