diff --git a/include/UpdateServer.h b/include/UpdateServer.h
index 3b992f6..c94c448 100644
--- a/include/UpdateServer.h
+++ b/include/UpdateServer.h
@@ -7,6 +7,11 @@
 class UpdateServer
 {
     public:
+        enum UpdateTypes {
+            UT_FLASH = 0,
+            UT_SPIFFS = 1
+        };
+
         UpdateServer(const std::string &pw);
 
         void start(void);
@@ -15,4 +20,4 @@ class UpdateServer
         static void updateTask(void *arg);
 
         ChallengeResponse m_cr;
-};
\ No newline at end of file
+};
diff --git a/scripts/ota_update.py b/scripts/ota_update.py
index 200731f..d0cfc88 100755
--- a/scripts/ota_update.py
+++ b/scripts/ota_update.py
@@ -9,6 +9,10 @@ import time
 
 from getpass import getpass
 
+# update types
+FLASH  = 0
+SPIFFS = 1
+
 def readMessage(sock):
     data = sock.recv(4)
     length, = struct.unpack(">I", data)
@@ -28,7 +32,15 @@ with open("../data/etc/auth", "r") as authFile:
             break
         lineno += 1
 
-_, host, port, filename = sys.argv
+_, host, port, updatetypestr, filename = sys.argv
+
+if updatetypestr == "flash":
+    updatetype = FLASH
+elif updatetypestr == "spiffs":
+    updatetype = SPIFFS
+else:
+    print(f"Invalid update type {updatetypestr}. Valid types are: flash, spiffs")
+    exit(1)
 
 # read and store the password from the user
 pwd = getpass()
@@ -70,8 +82,12 @@ print() # for proper progress display
 
 with open(filename, "rb") as binfile:
     filesize = os.stat(filename).st_size
+    messagesize = filesize + 1 # for type byte
 
-    data = struct.pack(">I", filesize)
+    data = struct.pack(">I", messagesize)
+    s.send(data)
+
+    data = struct.pack("B", updatetype)
     s.send(data)
 
     sent_bytes = 0
diff --git a/src/UpdateServer.cpp b/src/UpdateServer.cpp
index a2121da..dd6c2a1 100644
--- a/src/UpdateServer.cpp
+++ b/src/UpdateServer.cpp
@@ -119,11 +119,44 @@ void UpdateServer::updateTask(void *arg)
 
             len = be32toh(len);
 
+            if(len <= 1) {
+                Serial.println("Update message too small (expected >= 2 byte)");
+                sendMessage(&client, false, "Update message too small (expected >= 2 byte).");
+                client.stop();
+                continue;
+            }
+
+            len -= 1; // remove the previously read byte for type
+
+            // read update type
+            uint8_t update_type;
+            if(!read_n(&client, reinterpret_cast<char*>(&update_type), sizeof(update_type))) {
+                Serial.println("Read from update client (update type) failed.");
+                client.stop();
+                continue;
+            }
+
+            // translate to internal value
+            int update_command;
+            switch(update_type) {
+                case UT_FLASH:
+                    update_command = U_FLASH;
+                    break;
+                case UT_SPIFFS:
+                    update_command = U_SPIFFS;
+                    break;
+                default:
+                    Serial.println("Invalid update type.");
+                    sendMessage(&client, false, "Invalid update type");
+                    client.stop();
+                    continue;
+            }
+
             Serial.print("Update size: ");
             Serial.print(len);
             Serial.println(" Byte");
 
-            if(!Update.begin(len)) {
+            if(!Update.begin(len, update_command)) {
                 Serial.println("Cannot start update.");
                 sendMessage(&client, false, "Update failed.");
                 client.stop();
@@ -167,4 +200,4 @@ void UpdateServer::updateTask(void *arg)
 
         delay(100);
     }
-}
\ No newline at end of file
+}