diff --git a/Arduino/ReceiveCart/ReceiveCart.ino b/Arduino/ReceiveCart/ReceiveCart.ino
index b1a41d8..4534669 100644
--- a/Arduino/ReceiveCart/ReceiveCart.ino
+++ b/Arduino/ReceiveCart/ReceiveCart.ino
@@ -45,6 +45,7 @@ void setup() {
   Serial.begin(115200);
   pinMode(LED_BUILTIN, OUTPUT);
   Wire.begin();
+  Wire.setClock(400000);
 }
 
 void loop() {
diff --git a/Arduino/SendCart/SendCart.ino b/Arduino/SendCart/SendCart.ino
index 54de478..6bb0292 100644
--- a/Arduino/SendCart/SendCart.ino
+++ b/Arduino/SendCart/SendCart.ino
@@ -33,6 +33,7 @@ void setup() {
   Serial.begin(115200);
   pinMode(LED_BUILTIN, OUTPUT);
   Wire.begin();
+  Wire.setClock(400000);
 }
 
 /*
diff --git a/Assets/Scripts/Arduino_Com.cs b/Assets/Scripts/Arduino_Com.cs
index c5f1bad..bf7a9a3 100644
--- a/Assets/Scripts/Arduino_Com.cs
+++ b/Assets/Scripts/Arduino_Com.cs
@@ -14,6 +14,7 @@ public class Arduino_Com : MonoBehaviour
     {
         Déconnecté,
         Connecté,
+        Connexion,
         Lecture,
         Écriture,
         Invalide
@@ -68,16 +69,26 @@ public class Arduino_Com : MonoBehaviour
         return sum;
     }
     
+    // Core communication function.
+    // Receives all the data from the cartridge and writes it out to the png file.
+    // As the computer will probably read the serial data faster than the Arduino
+    // /and/ the transfer is quite slow (lots of bits, low baudrate), make this a
+    // coroutine.
+    // This prevents the whole application freezing up why waiting for data and
+    // allow presenting visual feedback.
     private IEnumerator<WaitUntil> ReceiveSerialData()
     {
         do
         {
+            // We could use an event instead but as Unity is lagging behind .NET versions,
+            // it wouldn't be cross-platform.
             yield return new WaitUntil(() => _serial.BytesToRead >= 1);
+            
             // Read all available data, up to the PageSize.
             _readBytes += _serial.Read(_pageBuffer, _readBytes, PageSize - _readBytes);
 
             // Full page received, check checksum and ACK/NAK, write received page.
-            if (_readBytes >= 128)
+            if (_readBytes >= PageSize)
             {
                 Byte[] checksum = new byte[2];
                 // There might be less than the two characters of the checksum available, loop until complete.
@@ -88,7 +99,8 @@ public class Arduino_Com : MonoBehaviour
                 } while (checksumRead < 2);
                 
                 // Implicit type of the sum is 4 bytes, so the overflow doesn't occur. Compute manually.
-                if (65536 - (BitConverter.ToUInt16(checksum) + ComputeChecksum(_pageBuffer)) == 0)
+                if ((UInt16.MaxValue + 1) -
+                    (BitConverter.ToUInt16(checksum) + ComputeChecksum(_pageBuffer)) == 0)
                 {
                     // Checksum valid, write it out to the cart.
                     _cart.Write(_pageBuffer);
@@ -104,6 +116,7 @@ public class Arduino_Com : MonoBehaviour
                 _readBytes = 0;
             }
         } while (_currentPage < PageCount);
+        
         // We are done receiving the cart, we don't expect more data to be received so the coroutine can return.
         _currentPage = 0;
         _state = ArduinoState.Connecté;
@@ -222,14 +235,7 @@ public class Arduino_Com : MonoBehaviour
                 return;
             }
             
-            // TODO: Wait ~2s for Arduino startup
-            _arduinoControlButton.text = "Déconnecter";
-            
-            _cartLoadButton.SetEnabled(true);
-            // _cartWriteButton.SetEnabled(true);  TODO: Not implemented
-            _arduinoSerialPort.SetEnabled(false);
-
-            _state = ArduinoState.Connecté;
+            StartCoroutine(DoSerialConnection());
         }
     }
     
@@ -244,4 +250,24 @@ public class Arduino_Com : MonoBehaviour
         _state = SerialPort.GetPortNames().Contains(newPort.newValue) ? ArduinoState.Déconnecté : ArduinoState.Invalide;
         _arduinoControlButton.SetEnabled(_state != ArduinoState.Invalide);
     }
+
+    // Update UI during connection and when ready, prevent interacting too quickly.
+    IEnumerator<WaitForSeconds> DoSerialConnection()
+    {
+        _arduinoControlButton.text = "Connexion...";
+        _arduinoControlButton.SetEnabled(false);
+        _arduinoSerialPort.SetEnabled(false);
+        _state = ArduinoState.Connexion;
+        
+        // Delay enabling transfers because the Arduino is slow to set-up the serial.
+        yield return new WaitForSeconds(1.5f);
+        
+        _arduinoControlButton.text = "Déconnecter";
+        _arduinoControlButton.SetEnabled(true);
+            
+        _cartLoadButton.SetEnabled(true);
+        // _cartWriteButton.SetEnabled(true);  TODO: Not implemented
+
+        _state = ArduinoState.Connecté;
+    }
 }