diff --git a/flags/subscription.aconfig b/flags/subscription.aconfig
index 32e8f2d..9a5dabc 100644
--- a/flags/subscription.aconfig
+++ b/flags/subscription.aconfig
@@ -65,3 +65,15 @@
     purpose: PURPOSE_BUGFIX
   }
 }
+
+# OWNER=songferngwang TARGET=24Q3
+flag {
+  name: "reset_primary_sim_default_values"
+  namespace: "telephony"
+  description: "Reset the default values to the remaining sim"
+  bug: "339394518"
+
+  metadata {
+    purpose: PURPOSE_BUGFIX
+  }
+}
diff --git a/src/java/com/android/internal/telephony/MultiSimSettingController.java b/src/java/com/android/internal/telephony/MultiSimSettingController.java
index 83d58af..49c7734 100644
--- a/src/java/com/android/internal/telephony/MultiSimSettingController.java
+++ b/src/java/com/android/internal/telephony/MultiSimSettingController.java
@@ -645,8 +645,11 @@
         // Otherwise, if user just inserted their first SIM, or there's one primary and one
         // opportunistic subscription active (activeSubInfos.size() > 1), we automatically
         // set the primary to be default SIM and return.
-        if (mPrimarySubList.size() == 1 && (change != PRIMARY_SUB_REMOVED
-                || mActiveModemCount == 1)) {
+        boolean conditionForOnePrimarySim =
+                mFeatureFlags.resetPrimarySimDefaultValues() ? mPrimarySubList.size() == 1
+                        : mPrimarySubList.size() == 1
+                        && (change != PRIMARY_SUB_REMOVED || mActiveModemCount == 1);
+        if (conditionForOnePrimarySim) {
             int subId = mPrimarySubList.get(0);
             if (DBG) log("updateDefaultValues: to only primary sub " + subId);
             if (hasData()) mSubscriptionManagerService.setDefaultDataSubId(subId);
diff --git a/tests/telephonytests/src/com/android/internal/telephony/MultiSimSettingControllerTest.java b/tests/telephonytests/src/com/android/internal/telephony/MultiSimSettingControllerTest.java
index a6b2000..855a5dc 100644
--- a/tests/telephonytests/src/com/android/internal/telephony/MultiSimSettingControllerTest.java
+++ b/tests/telephonytests/src/com/android/internal/telephony/MultiSimSettingControllerTest.java
@@ -18,10 +18,8 @@
 
 import static android.telephony.TelephonyManager.ACTION_PRIMARY_SUBSCRIPTION_LIST_CHANGED;
 import static android.telephony.TelephonyManager.EXTRA_DEFAULT_SUBSCRIPTION_SELECT_TYPE;
-import static android.telephony.TelephonyManager.EXTRA_DEFAULT_SUBSCRIPTION_SELECT_TYPE_ALL;
 import static android.telephony.TelephonyManager.EXTRA_DEFAULT_SUBSCRIPTION_SELECT_TYPE_DATA;
 import static android.telephony.TelephonyManager.EXTRA_DEFAULT_SUBSCRIPTION_SELECT_TYPE_DISMISS;
-import static android.telephony.TelephonyManager.EXTRA_SUBSCRIPTION_ID;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
@@ -251,6 +249,8 @@
         bundle.putBoolean(CarrierConfigManager.KEY_CARRIER_CONFIG_APPLIED_BOOL, true);
         doReturn(bundle).when(mCarrierConfigManager).getConfigForSubId(anyInt());
 
+        doReturn(true).when(mFeatureFlags).resetPrimarySimDefaultValues();
+
         replaceInstance(PhoneFactory.class, "sPhones", null, mPhones);
         // Capture listener to emulate the carrier config change notification used later
         ArgumentCaptor<CarrierConfigManager.CarrierConfigChangeListener> listenerArgumentCaptor =
@@ -496,18 +496,9 @@
         sendCarrierConfigChanged(1, SubscriptionManager.INVALID_SUBSCRIPTION_ID);
         processAllMessages();
 
-        verify(mSubscriptionManagerService).setDefaultDataSubId(
-                SubscriptionManager.INVALID_SUBSCRIPTION_ID);
-        verify(mSubscriptionManagerService).setDefaultSmsSubId(
-                SubscriptionManager.INVALID_SUBSCRIPTION_ID);
-        verify(mSubscriptionManagerService, never()).setDefaultVoiceSubId(anyInt());
-
-        // Verify intent sent to select sub 2 as default for all types.
-        Intent intent = captureBroadcastIntent();
-        assertEquals(ACTION_PRIMARY_SUBSCRIPTION_LIST_CHANGED, intent.getAction());
-        assertEquals(EXTRA_DEFAULT_SUBSCRIPTION_SELECT_TYPE_ALL,
-                intent.getIntExtra(EXTRA_DEFAULT_SUBSCRIPTION_SELECT_TYPE, -1));
-        assertEquals(2, intent.getIntExtra(EXTRA_SUBSCRIPTION_ID, -1));
+        verify(mSubscriptionManagerService).setDefaultDataSubId(2);
+        verify(mSubscriptionManagerService).setDefaultSmsSubId(2);
+        verify(mSubscriptionManagerService).setDefaultVoiceSubId(2);
     }
 
     @Test
@@ -917,8 +908,7 @@
         markSubscriptionInactive(1/*subid*/);
         sendCarrierConfigChanged(0/*phoneid*/, SubscriptionManager.INVALID_SUBSCRIPTION_ID);
 
-        verify(mSubscriptionManagerService).setDefaultDataSubId(
-                SubscriptionManager.INVALID_SUBSCRIPTION_ID);
+        verify(mSubscriptionManagerService).setDefaultDataSubId(2);
 
         // insert it back, but carrier config not loaded yet
         clearInvocations(mSubscriptionManagerService);