diff --git a/Ble.jar b/Ble.jar
index f52d79b..fb85bb4 100644
Binary files a/Ble.jar and b/Ble.jar differ
diff --git a/BleConnect.java b/BleConnect.java
index 604c404..b4e4d69 100644
--- a/BleConnect.java
+++ b/BleConnect.java
@@ -126,6 +126,13 @@ public class BleConnect extends Fragment {
 		public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
 			BluetoothDevice device = gatt.getDevice();
 			String addr = device.getAddress();
+			if (status != BluetoothGatt.GATT_SUCCESS) {
+				Log.d("gio", "onConnectionStateChange: error code " + status);
+				onDisconnect(gatt, addr);
+				Log.d("gio", "gatt.close()");
+				gatt.close();
+				return;
+			}
 			switch (newState) {
 				case BluetoothProfile.STATE_CONNECTED: {
 					Log.d("gio", "Connected");
@@ -133,14 +140,21 @@ public class BleConnect extends Fragment {
 					onConnect(gatt, addr);
 					break;
 				}
+				case BluetoothProfile.STATE_CONNECTING:
+				case BluetoothProfile.STATE_DISCONNECTING: {
+					break;
+				}
 				case BluetoothProfile.STATE_DISCONNECTED: {
 					Log.d("gio", "Disconnected");
 					onDisconnect(gatt, addr);
+					Log.d("gio", "gatt.close()");
 					gatt.close();
 					break;
 				}
 				default: {
 					Log.d("gio", "onConnectionStateChange: unknown state");
+					onDisconnect(gatt, addr);
+					Log.d("gio", "gatt.close()");
 					gatt.close();
 					break;
 				}
@@ -177,7 +191,15 @@ public class BleConnect extends Fragment {
 		Log.d("gio","BleConnect: disconnect");
 		handler.post(new Runnable() {
 			public void run() {
+				boolean callClose = false;
+				BluetoothDevice device = gatt.getDevice();
+				if (device != null) {
+					callClose = (manager.getConnectionState(device, BluetoothProfile.GATT) != BluetoothGatt.STATE_CONNECTED);
+				}
 				gatt.disconnect();
+				if (callClose) {
+					gatt.close();
+				}
 			}
 		});
 	}
diff --git a/ble_android.go b/ble_android.go
index 8baf4c0..c1d4074 100644
--- a/ble_android.go
+++ b/ble_android.go
@@ -178,6 +178,9 @@ func (b *BLE) knownPeripheral(p Peripheral) (Peripheral, bool) {
 
 //DiscoverServices asks a Peripheral for its Services
 func (p Peripheral) DiscoverServices() {
+	if p.gatt == 0 {
+		return
+	}
 	connect()
 	log.Printf("discovering services")
 	runInJVM(func(env *C.JNIEnv) {
@@ -188,6 +191,9 @@ func (p Peripheral) DiscoverServices() {
 //DiscoverCharacteristics asks a Peripheral for the Characteristics related
 //to a Service
 func (p Peripheral) DiscoverCharacteristics(serv Service) {
+	if p.gatt == 0 {
+		return
+	}
 	//launch a goroutine because this function calls back directly
 	//from the same thread.
 	go func() {
@@ -202,6 +208,9 @@ func (p Peripheral) DiscoverCharacteristics(serv Service) {
 
 //SetNotifyValue subscribes to a characteristic
 func (p Peripheral) SetNotifyValue(c Characteristic) {
+	if p.gatt == 0 {
+		return
+	}
 	runInJVM(func(env *C.JNIEnv) {
 		log.Printf("setCharacteristicNotification: %s", c.UUID)
 		C.setCharacteristicNotification(env, gBLE.handle.BleConnect, p.gatt, c.characteristic)