diff --git a/USBNova.ino b/USBNova.ino
index 137c8f9..b0476e8 100644
--- a/USBNova.ino
+++ b/USBNova.ino
@@ -49,8 +49,9 @@ void setup() {
     if(mode == SETUP && preferences::getFormat()) {
         led::setColor(255,255,255);
         format::start(preferences::getDriveName().c_str());
+        preferences::save();
     }
-    
+
     // ==========  Setup Mode ==========  //
     if (mode == SETUP) {
         led::setColor(preferences::getSetupColor()); // Set LED to blue
diff --git a/src/msc/msc.cpp b/src/msc/msc.cpp
index 0adf4b4..bf5e15e 100644
--- a/src/msc/msc.cpp
+++ b/src/msc/msc.cpp
@@ -70,7 +70,7 @@ namespace msc {
         flash.begin();
         fatfs.begin(&flash);
     }
-    
+
     void setID(const char* vid, const char* pid, const char* rev) {
         usb_msc.setID(vid, pid, rev); // Max. 8, 16, 4 characters
     }
@@ -89,7 +89,7 @@ namespace msc {
         return tmp;
     }
 
-    bool open(const char* path) {
+    bool open(const char* path, bool write) {
         debug("Open new file: ");
         debugln(path);
 
@@ -111,22 +111,14 @@ namespace msc {
         file_stack.push(file_element);
 
         // Open file and return whether it was successful
-        return file.open(path);
+        return file.open(path, write ? (O_RDWR | O_CREAT) : O_RDONLY);
     }
 
     bool openNextFile() {
         debug("Opening next file: ");
 
         // Close current file and remove it from stack (it's not needed anymore)
-        debug("Stack (before file close): ");
-        debugln(file_stack.size());
-        debugln(file_stack.top().path.c_str());
-
-        file.close();
-        file_stack.pop();
-
-        debug("Stack (after file close): ");
-        debugln(file_stack.size());
+        close();
 
         // If stack is now empty, we're done
         if (file_stack.empty()) {
@@ -153,6 +145,19 @@ namespace msc {
         return false;
     }
 
+    void close() {
+        // Close current file and remove it from stack (it's not needed anymore)
+        debug("Stack (before file close): ");
+        debugln(file_stack.size());
+        debugln(file_stack.top().path.c_str());
+
+        file.close();
+        file_stack.pop();
+
+        debug("Stack (after file close): ");
+        debugln(file_stack.size());
+    }
+
     uint32_t getPosition() {
         return file.curPosition();
     }
@@ -204,4 +209,10 @@ namespace msc {
     bool getInLine() {
         return in_line;
     }
+
+    size_t write(const char* buffer, size_t len) {
+        if (!file.isOpen()) return 0;
+
+        return file.write(buffer, len);
+    }
 }
\ No newline at end of file
diff --git a/src/msc/msc.h b/src/msc/msc.h
index 80db6ce..e8b761d 100644
--- a/src/msc/msc.h
+++ b/src/msc/msc.h
@@ -6,11 +6,16 @@
 
 namespace msc {
     void init();
+
     void setID(const char* vid, const char* pid, const char* rev);
     void enableDrive();
+
     bool changed();
-    bool open(const char* path);
+
+    bool open(const char* path, bool write = false);
     bool openNextFile();
+    
+    void close();
 
     uint32_t getPosition();
     void gotoPosition(uint32_t pos);
@@ -18,4 +23,6 @@ namespace msc {
     size_t read(char* buffer, size_t len);
     size_t readLine(char* buffer, size_t len);
     bool getInLine();
+
+    size_t write(const char* buffer, size_t len);
 }
\ No newline at end of file
diff --git a/src/preferences/preferences.cpp b/src/preferences/preferences.cpp
index d16f5bd..3284702 100644
--- a/src/preferences/preferences.cpp
+++ b/src/preferences/preferences.cpp
@@ -33,6 +33,39 @@ namespace preferences {
     bool format { false };
     std::string drive_name { "USB Nova" };
 
+    void toJson(JsonDocument& root) {
+        root["enable_msc"] = enable_msc;
+        root["enable_led"] = enable_led;
+
+        root["hid_vid"] = hid_vid;
+        root["hid_pid"] = hid_pid;
+        root["hid_rev"] = hid_rev;
+
+        root["msc_vid"] = msc_vid;
+        root["msc_pid"] = msc_pid;
+        root["msc_rev"] = msc_rev;
+
+        root["default_layout"] = default_layout;
+        root["default_delay"]  = default_delay;
+
+        root["main_script"] = main_script;
+
+        JsonArray attack_color_arr = root.createNestedArray("attack_color");
+        attack_color_arr.add(attack_color[0]);
+        attack_color_arr.add(attack_color[1]);
+        attack_color_arr.add(attack_color[2]);
+
+        JsonArray setup_color_arr = root.createNestedArray("setup_color");
+        setup_color_arr.add(setup_color[0]);
+        setup_color_arr.add(setup_color[1]);
+        setup_color_arr.add(setup_color[2]);
+
+        JsonArray idle_color_arr = root.createNestedArray("idle_color");
+        idle_color_arr.add(idle_color[0]);
+        idle_color_arr.add(idle_color[1]);
+        idle_color_arr.add(idle_color[2]);
+    }
+
     // ======== PUBLIC ======== //
     void load() {
         // Read config file
@@ -83,7 +116,7 @@ namespace preferences {
             arr.add(setup_color[1]);
             arr.add(setup_color[2]);
         }
-        
+
         if (!config_doc.containsKey("idle_color")) {
             JsonArray arr = config_doc.createNestedArray("idle_color");
             arr.add(idle_color[0]);
@@ -136,6 +169,29 @@ namespace preferences {
         }
     }
 
+    void save() {
+        // Create a new JSON document (and string buffer)
+        StaticJsonDocument<1024> json_doc;
+        // JsonObject json_obj = json_doc.as<JsonObject>();
+        std::string json_str = { "" };
+
+        // Add values
+        toJson(json_doc);
+
+        // Serialize JSON to buffer
+        serializeJsonPretty(json_doc, json_str);
+
+        // Write the buffer to file
+        msc::open("preferences.json", true);
+        debugln(json_str.length());
+        debugln(msc::write(json_str.c_str(), json_str.length()));
+        msc::close();
+
+        //debugln(json_str.length());
+        //debugln(json_str.c_str());
+        debugln("Saved preferences.json");
+    }
+
     bool mscEnabled() {
         return enable_msc;
     }
diff --git a/src/preferences/preferences.h b/src/preferences/preferences.h
index 3f5d7f0..2ae0b8a 100644
--- a/src/preferences/preferences.h
+++ b/src/preferences/preferences.h
@@ -6,6 +6,7 @@
 
 namespace preferences {
     void load();
+    void save();
 
     bool mscEnabled();
     bool ledEnabled();