diff --git a/app/src/main/java/com/xypower/mpapp/MainActivity.java b/app/src/main/java/com/xypower/mpapp/MainActivity.java
index 2f5dc42b..a43fd53c 100644
--- a/app/src/main/java/com/xypower/mpapp/MainActivity.java
+++ b/app/src/main/java/com/xypower/mpapp/MainActivity.java
@@ -110,6 +110,13 @@ public class MainActivity extends AppCompatActivity {
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
+        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.R) {
+            int activeSubId = SubscriptionManager.getActiveDataSubscriptionId();
+            if (activeSubId == -1) {
+                MicroPhotoContext.selectSimCard(getApplicationContext(), 1);
+            }
+        }
+
         binding = ActivityMainBinding.inflate(getLayoutInflater());
         setContentView(binding.getRoot());
         // getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);
diff --git a/common/src/main/java/com/xypower/common/MicroPhotoContext.java b/common/src/main/java/com/xypower/common/MicroPhotoContext.java
index 23923425..01767292 100644
--- a/common/src/main/java/com/xypower/common/MicroPhotoContext.java
+++ b/common/src/main/java/com/xypower/common/MicroPhotoContext.java
@@ -4,9 +4,13 @@ import android.app.ActivityManager;
 import android.content.Context;
 import android.content.Intent;
 import android.content.pm.PackageManager;
+import android.os.Build;
 import android.os.Environment;
 import android.os.storage.StorageManager;
+import android.telephony.SubscriptionManager;
+import android.telephony.TelephonyManager;
 import android.text.TextUtils;
+import android.util.Log;
 
 import com.dev.devapi.api.SysApi;
 
@@ -492,5 +496,59 @@ public class MicroPhotoContext {
         return versionCode;
     }
 
+    public static boolean selectSimCard(final Context context, int num) {
+
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
+
+            SubscriptionManager subscriptionManager = (SubscriptionManager) context.getSystemService(Context.TELEPHONY_SUBSCRIPTION_SERVICE);
+            int activeSubId = SubscriptionManager.getActiveDataSubscriptionId();
+            int activeSlotIdx = SubscriptionManager.getSlotIndex(activeSubId);
+            if (activeSlotIdx == (num - 1)) {
+                // logger.info("Active SimCard is already " + Integer.toString(num));
+            } else {
+                int subIds[] = subscriptionManager.getSubscriptionIds(num - 1);
+                if (subIds != null && subIds.length > 0) {
+                    setDefaultDataSubId(context, subIds[0]);
+                    // logger.info("Switched To SimCard: " + Integer.toString(num));
+                }
+            }
+        } else {
+            SysApi.selectSimCard4Data(context, num);
+        }
+
+        return true;
+    }
+
+    private static void setDefaultDataSubId(final Context context, int subId) {
+        SubscriptionManager subscriptionManager = (SubscriptionManager) context.getSystemService(Context.TELEPHONY_SUBSCRIPTION_SERVICE);
+        try {
+
+            Method method = subscriptionManager.getClass().getDeclaredMethod("setDefaultDataSubId", int.class);
+            try {
+                method.invoke(subscriptionManager, subId);
+            } catch (Exception ex) {
+                ex.printStackTrace();
+            }
+            TelephonyManager telephonyManager = (TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE);
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+                telephonyManager.setDataEnabled(true);
+            }
+            Method method1 = telephonyManager.getClass().getDeclaredMethod("setDataEnabled", boolean.class);
+            method1.invoke(telephonyManager, true);
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+    private static int getDefaultDataSubId(final Context context) {
+        SubscriptionManager subscriptionManager = (SubscriptionManager) context.getSystemService(Context.TELEPHONY_SUBSCRIPTION_SERVICE);
+        try {
+            Method method = subscriptionManager.getClass().getDeclaredMethod("getDefaultDataSubscriptionId");
+            return (int) method.invoke(subscriptionManager);
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+        return 0;
+    }
 
 }