diff --git a/src/java/com/android/internal/telephony/MultiSimSettingController.java b/src/java/com/android/internal/telephony/MultiSimSettingController.java
index 11ad9a6..4206b5f 100644
--- a/src/java/com/android/internal/telephony/MultiSimSettingController.java
+++ b/src/java/com/android/internal/telephony/MultiSimSettingController.java
@@ -31,13 +31,16 @@
 import android.annotation.IntDef;
 import android.annotation.NonNull;
 import android.app.PendingIntent;
+import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
+import android.content.IntentFilter;
 import android.os.Handler;
 import android.os.Message;
 import android.os.ParcelUuid;
 import android.provider.Settings;
 import android.provider.Settings.SettingNotFoundException;
+import android.telephony.CarrierConfigManager;
 import android.telephony.SubscriptionInfo;
 import android.telephony.SubscriptionManager;
 import android.telephony.TelephonyManager;
@@ -51,6 +54,7 @@
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 import java.util.stream.Collectors;
 
@@ -73,6 +77,7 @@
     private static final int EVENT_SUBSCRIPTION_INFO_CHANGED         = 4;
     private static final int EVENT_SUBSCRIPTION_GROUP_CHANGED        = 5;
     private static final int EVENT_DEFAULT_DATA_SUBSCRIPTION_CHANGED = 6;
+    private static final int EVENT_CARRIER_CONFIG_CHANGED            = 7;
 
     @Retention(RetentionPolicy.SOURCE)
     @IntDef(prefix = {"PRIMARY_SUB_"},
@@ -118,6 +123,32 @@
     // the SIMs are newly inserted instead of being initialized.
     private boolean mSubInfoInitialized = false;
 
+    // mInitialHandling is to make sure we don't always ask user to re-select data SIM after reboot.
+    // After boot-up when things are firstly initialized (mSubInfoInitialized is changed to true
+    // and carrier configs are all loaded), we do a reEvaluateAll(). In the first reEvaluateAll(),
+    // mInitialHandling will be true and we won't pop up SIM select dialog.
+    private boolean mInitialHandling = true;
+
+    // Keep a record of which subIds have carrier config loaded. Length of the array is phone count.
+    // The index is phoneId, and value is subId. For example:
+    // If carrier config of subId 2 is loaded on phone 0,mCarrierConfigLoadedSubIds[0] = 2.
+    // Then if subId 2 is deactivated from phone 0, the value becomes INVALID,
+    // mCarrierConfigLoadedSubIds[0] = INVALID_SUBSCRIPTION_ID.
+    private int[] mCarrierConfigLoadedSubIds;
+
+    private final BroadcastReceiver mIntentReceiver = new BroadcastReceiver() {
+        @Override
+        public void onReceive(Context context, Intent intent) {
+            if (CarrierConfigManager.ACTION_CARRIER_CONFIG_CHANGED.equals(intent.getAction())) {
+                int phoneId = intent.getIntExtra(CarrierConfigManager.EXTRA_SLOT_INDEX,
+                        SubscriptionManager.INVALID_SIM_SLOT_INDEX);
+                int subId = intent.getIntExtra(CarrierConfigManager.EXTRA_SUBSCRIPTION_INDEX,
+                        SubscriptionManager.INVALID_SUBSCRIPTION_ID);
+                notifyCarrierConfigChanged(phoneId, subId);
+            }
+        }
+    };
+
     /**
      * Return the singleton or create one if not existed.
      */
@@ -149,6 +180,15 @@
     public MultiSimSettingController(Context context, SubscriptionController sc) {
         mContext = context;
         mSubController = sc;
+
+        // Initialize mCarrierConfigLoadedSubIds and register to listen to carrier config change.
+        final int phoneCount = ((TelephonyManager) mContext.getSystemService(
+                Context.TELEPHONY_SERVICE)).getPhoneCount();
+        mCarrierConfigLoadedSubIds = new int[phoneCount];
+        Arrays.fill(mCarrierConfigLoadedSubIds, SubscriptionManager.INVALID_SUBSCRIPTION_ID);
+
+        context.registerReceiver(mIntentReceiver, new IntentFilter(
+                CarrierConfigManager.ACTION_CARRIER_CONFIG_CHANGED));
     }
 
     /**
@@ -222,6 +262,11 @@
             case EVENT_DEFAULT_DATA_SUBSCRIPTION_CHANGED:
                 onDefaultDataSettingChanged();
                 break;
+            case EVENT_CARRIER_CONFIG_CHANGED:
+                int phoneId = msg.arg1;
+                int subId = msg.arg2;
+                onCarrierConfigChanged(phoneId, subId);
+                break;
         }
     }
 
@@ -261,9 +306,7 @@
     private void onAllSubscriptionsLoaded() {
         if (DBG) log("onAllSubscriptionsLoaded");
         mSubInfoInitialized = true;
-        updateDefaults(/*init*/ true);
-        disableDataForNonDefaultNonOpportunisticSubscriptions();
-        deactivateGroupedOpportunisticSubscriptionIfNeeded();
+        reEvaluateAll();
     }
 
     /**
@@ -273,8 +316,58 @@
      */
     private void onSubscriptionsChanged() {
         if (DBG) log("onSubscriptionsChanged");
-        if (!mSubInfoInitialized) return;
-        updateDefaults(/*init*/ false);
+        reEvaluateAll();
+    }
+
+    /**
+     * Called when carrier config changes on any phone.
+     */
+    @VisibleForTesting
+    public void notifyCarrierConfigChanged(int phoneId, int subId) {
+        obtainMessage(EVENT_CARRIER_CONFIG_CHANGED, phoneId, subId).sendToTarget();
+    }
+
+    private void onCarrierConfigChanged(int phoneId, int subId) {
+        log("onCarrierConfigChanged phoneId " + phoneId + " subId " + subId);
+        if (!SubscriptionManager.isValidPhoneId(phoneId)) {
+            loge("Carrier config change with invalid phoneId " + phoneId);
+            return;
+        }
+
+        mCarrierConfigLoadedSubIds[phoneId] = subId;
+        reEvaluateAll();
+    }
+
+    private boolean isCarrierConfigLoadedForAllSub() {
+        int[] activeSubIds = mSubController.getActiveSubIdList(false);
+        for (int activeSubId : activeSubIds) {
+            boolean isLoaded = false;
+            for (int configLoadedSub : mCarrierConfigLoadedSubIds) {
+                if (configLoadedSub == activeSubId) {
+                    isLoaded = true;
+                    break;
+                }
+            }
+            if (!isLoaded) {
+                if (DBG) log("Carrier config subId " + activeSubId + " is not loaded.");
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    /**
+     * Wait for subInfo initialization (after boot up) and carrier config load for all active
+     * subscriptions before re-evaluate multi SIM settings.
+     */
+    private boolean isReadyToReevaluate() {
+        return mSubInfoInitialized && isCarrierConfigLoadedForAllSub();
+    }
+
+    private void reEvaluateAll() {
+        if (!isReadyToReevaluate()) return;
+        updateDefaults();
         disableDataForNonDefaultNonOpportunisticSubscriptions();
         deactivateGroupedOpportunisticSubscriptionIfNeeded();
     }
@@ -353,12 +446,11 @@
      *    not a user settable value anymore.
      * 4) If non above is met, clear the default value to INVALID.
      *
-     * @param init whether the subscriptions are just initialized.
      */
-    private void updateDefaults(boolean init) {
+    private void updateDefaults() {
         if (DBG) log("updateDefaults");
 
-        if (!mSubInfoInitialized) return;
+        if (!isReadyToReevaluate()) return;
 
         List<SubscriptionInfo> activeSubInfos = mSubController
                 .getActiveSubscriptionInfoList(mContext.getOpPackageName());
@@ -372,7 +464,7 @@
             return;
         }
 
-        int change = updatePrimarySubListAndGetChangeType(activeSubInfos, init);
+        int change = updatePrimarySubListAndGetChangeType(activeSubInfos);
         if (DBG) log("[updateDefaultValues] change: " + change);
         if (change == PRIMARY_SUB_NO_CHANGE) return;
 
@@ -414,8 +506,7 @@
     }
 
     @PrimarySubChangeType
-    private int updatePrimarySubListAndGetChangeType(List<SubscriptionInfo> activeSubList,
-            boolean init) {
+    private int updatePrimarySubListAndGetChangeType(List<SubscriptionInfo> activeSubList) {
         // Update mPrimarySubList. Opportunistic subscriptions can't be default
         // data / voice / sms subscription.
         List<Integer> prevPrimarySubList = mPrimarySubList;
@@ -423,7 +514,10 @@
                 .map(info -> info.getSubscriptionId())
                 .collect(Collectors.toList());
 
-        if (init) return PRIMARY_SUB_INITIALIZED;
+        if (mInitialHandling) {
+            mInitialHandling = false;
+            return PRIMARY_SUB_INITIALIZED;
+        }
         if (mPrimarySubList.equals(prevPrimarySubList)) return PRIMARY_SUB_NO_CHANGE;
         if (mPrimarySubList.size() > prevPrimarySubList.size()) return PRIMARY_SUB_ADDED;
 
@@ -554,7 +648,7 @@
     }
 
     private void disableDataForNonDefaultNonOpportunisticSubscriptions() {
-        if (!mSubInfoInitialized) return;
+        if (!isReadyToReevaluate()) return;
 
         int defaultDataSub = mSubController.getDefaultDataSubId();
 
diff --git a/tests/telephonytests/src/com/android/internal/telephony/MultiSimSettingControllerTest.java b/tests/telephonytests/src/com/android/internal/telephony/MultiSimSettingControllerTest.java
index 74bbb82..70ebfb9 100644
--- a/tests/telephonytests/src/com/android/internal/telephony/MultiSimSettingControllerTest.java
+++ b/tests/telephonytests/src/com/android/internal/telephony/MultiSimSettingControllerTest.java
@@ -118,6 +118,7 @@
         List<SubscriptionInfo> infoList = Arrays.asList(mSubInfo1, mSubInfo2);
         doReturn(infoList).when(mSubControllerMock)
                 .getActiveSubscriptionInfoList(anyString());
+        doReturn(new int[]{1, 2}).when(mSubControllerMock).getActiveSubIdList(anyBoolean());
 
         mPhones = new Phone[] {mPhoneMock1, mPhoneMock2};
         doReturn(mDataEnabledSettingsMock1).when(mPhoneMock1).getDataEnabledSettings();
@@ -175,6 +176,7 @@
         doReturn(SubscriptionManager.INVALID_SUBSCRIPTION_ID).when(mPhoneMock2).getSubId();
         List<SubscriptionInfo> infoList = Arrays.asList(mSubInfo1);
         doReturn(infoList).when(mSubControllerMock).getActiveSubscriptionInfoList(anyString());
+        doReturn(new int[]{1}).when(mSubControllerMock).getActiveSubIdList(anyBoolean());
 
         // Mark subscription ready as false. The below sub info change should be ignored.
         mMultiSimSettingControllerUT.notifySubscriptionInfoChanged();
@@ -184,6 +186,7 @@
         verify(mSubControllerMock, never()).setDefaultSmsSubId(anyInt());
 
         mMultiSimSettingControllerUT.notifyAllSubscriptionLoaded();
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(0, 1);
         waitABit();
 
         // Sub 1 should be default sub silently.
@@ -210,8 +213,10 @@
         doReturn(SubscriptionManager.INVALID_SUBSCRIPTION_ID).when(mPhoneMock2).getSubId();
         List<SubscriptionInfo> infoList = Arrays.asList(mSubInfo1);
         doReturn(infoList).when(mSubControllerMock).getActiveSubscriptionInfoList(anyString());
+        doReturn(new int[]{1}).when(mSubControllerMock).getActiveSubIdList(anyBoolean());
 
         mMultiSimSettingControllerUT.notifyAllSubscriptionLoaded();
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(0, 1);
         waitABit();
 
         // Sub 1 should be default sub silently.
@@ -223,8 +228,10 @@
         doReturn(2).when(mPhoneMock1).getSubId();
         infoList = Arrays.asList(mSubInfo2);
         doReturn(infoList).when(mSubControllerMock).getActiveSubscriptionInfoList(anyString());
+        doReturn(new int[]{2}).when(mSubControllerMock).getActiveSubIdList(anyBoolean());
 
         mMultiSimSettingControllerUT.notifySubscriptionInfoChanged();
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(0, 2);
         waitABit();
 
         // Sub 1 should be default sub silently.
@@ -244,8 +251,10 @@
         doReturn(SubscriptionManager.INVALID_SUBSCRIPTION_ID).when(mPhoneMock2).getSubId();
         List<SubscriptionInfo> infoList = Arrays.asList(mSubInfo1);
         doReturn(infoList).when(mSubControllerMock).getActiveSubscriptionInfoList(anyString());
+        doReturn(new int[]{1}).when(mSubControllerMock).getActiveSubIdList(anyBoolean());
 
         mMultiSimSettingControllerUT.notifyAllSubscriptionLoaded();
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(0, 1);
         waitABit();
 
         // Sub 1 should be default sub silently.
@@ -262,8 +271,10 @@
         doReturn(2).when(mPhoneMock2).getSubId();
         infoList = Arrays.asList(mSubInfo1, mSubInfo2);
         doReturn(infoList).when(mSubControllerMock).getActiveSubscriptionInfoList(anyString());
+        doReturn(new int[]{1, 2}).when(mSubControllerMock).getActiveSubIdList(anyBoolean());
 
         mMultiSimSettingControllerUT.notifySubscriptionInfoChanged();
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(1, 2);
         waitABit();
 
         // Intent should be broadcast to ask default data selection.
@@ -282,8 +293,10 @@
         doReturn(3).when(mPhoneMock2).getSubId();
         infoList = Arrays.asList(mSubInfo1, mSubInfo3);
         doReturn(infoList).when(mSubControllerMock).getActiveSubscriptionInfoList(anyString());
+        doReturn(new int[]{1, 3}).when(mSubControllerMock).getActiveSubIdList(anyBoolean());
 
         mMultiSimSettingControllerUT.notifySubscriptionInfoChanged();
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(1, 3);
         waitABit();
 
         // Intent should be broadcast to ask default data selection.
@@ -300,6 +313,8 @@
         doReturn(true).when(mPhoneMock2).isUserDataEnabled();
         // After initialization, sub 2 should have mobile data off.
         mMultiSimSettingControllerUT.notifyAllSubscriptionLoaded();
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(0, 1);
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(1, 2);
         waitABit();
         verify(mDataEnabledSettingsMock2).setUserDataEnabled(false);
 
@@ -323,7 +338,10 @@
         doReturn(false).when(mSubControllerMock).isActiveSubId(1);
         List<SubscriptionInfo> infoList = Arrays.asList(mSubInfo2);
         doReturn(infoList).when(mSubControllerMock).getActiveSubscriptionInfoList(anyString());
+        doReturn(new int[]{2}).when(mSubControllerMock).getActiveSubIdList(anyBoolean());
         mMultiSimSettingControllerUT.notifySubscriptionInfoChanged();
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(
+                1, SubscriptionManager.INVALID_SUBSCRIPTION_ID);
         waitABit();
         verify(mSubControllerMock).setDefaultDataSubId(SubscriptionManager.INVALID_SUBSCRIPTION_ID);
         verify(mSubControllerMock).setDefaultSmsSubId(SubscriptionManager.INVALID_SUBSCRIPTION_ID);
@@ -346,6 +364,8 @@
         GlobalSettingsHelper.setBoolean(mContext, Settings.Global.MOBILE_DATA, 2, true);
         GlobalSettingsHelper.setBoolean(mContext, Settings.Global.DATA_ROAMING, 2, false);
         mMultiSimSettingControllerUT.notifyAllSubscriptionLoaded();
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(0, 1);
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(1, 2);
         waitABit();
 
         // Create subscription grouping.
@@ -391,8 +411,10 @@
         doReturn(1).when(mSubControllerMock).getDefaultVoiceSubId();
         List<SubscriptionInfo> infoList = Arrays.asList(mSubInfo1, mSubInfo3);
         doReturn(infoList).when(mSubControllerMock).getActiveSubscriptionInfoList(anyString());
+        doReturn(new int[]{1, 3}).when(mSubControllerMock).getActiveSubIdList(anyBoolean());
 
         mMultiSimSettingControllerUT.notifySubscriptionInfoChanged();
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(1, 3);
         waitABit();
 
         verify(mSubControllerMock).setDefaultDataSubId(3);
@@ -414,6 +436,8 @@
         // Notify subscriptions ready. Sub 2 should become the default. But shouldn't turn off
         // data of oppt sub 1.
         mMultiSimSettingControllerUT.notifyAllSubscriptionLoaded();
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(0, 1);
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(1, 2);
         waitABit();
         verify(mSubControllerMock).setDefaultDataSubId(2);
         verify(mDataEnabledSettingsMock1, never()).setUserDataEnabled(anyBoolean());
@@ -451,6 +475,8 @@
 
         // Notify subscriptions ready. Sub 2 should become the default, as sub 1 is opportunistic.
         mMultiSimSettingControllerUT.notifyAllSubscriptionLoaded();
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(0, 1);
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(1, 2);
         waitABit();
         verify(mSubControllerMock).setDefaultDataSubId(2);
         // No user selection needed, no intent should be sent.
@@ -494,6 +520,8 @@
         GlobalSettingsHelper.setBoolean(mContext, Settings.Global.MOBILE_DATA, 1, true);
         GlobalSettingsHelper.setBoolean(mContext, Settings.Global.DATA_ROAMING, 1, false);
         mMultiSimSettingControllerUT.notifyAllSubscriptionLoaded();
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(0, 1);
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(1, 2);
         waitABit();
 
         // Create subscription grouping.
@@ -514,4 +542,46 @@
         waitABit();
         verify(mDataEnabledSettingsMock2).setUserDataEnabled(false);
     }
+
+    @Test
+    @SmallTest
+    public void testCarrierConfigLoading() throws Exception {
+        doReturn(true).when(mPhoneMock1).isUserDataEnabled();
+        doReturn(true).when(mPhoneMock2).isUserDataEnabled();
+        // Sub 2 should have mobile data off, but it shouldn't happen until carrier configs are
+        // loaded on both subscriptions.
+        mMultiSimSettingControllerUT.notifyAllSubscriptionLoaded();
+        waitABit();
+        verify(mDataEnabledSettingsMock2, never()).setUserDataEnabled(false);
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(0, 1);
+        waitABit();
+        verify(mDataEnabledSettingsMock2, never()).setUserDataEnabled(false);
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(1, 2);
+        waitABit();
+        verify(mDataEnabledSettingsMock2).setUserDataEnabled(false);
+
+        // Switch from sub 2 to sub 3 in phone[1].
+        clearInvocations(mSubControllerMock);
+        doReturn(false).when(mSubControllerMock).isActiveSubId(2);
+        doReturn(true).when(mSubControllerMock).isActiveSubId(3);
+        doReturn(SubscriptionManager.INVALID_PHONE_INDEX).when(mSubControllerMock).getPhoneId(2);
+        doReturn(1).when(mSubControllerMock).getPhoneId(3);
+        doReturn(3).when(mPhoneMock2).getSubId();
+        List<SubscriptionInfo> infoList = Arrays.asList(mSubInfo1, mSubInfo3);
+        doReturn(infoList).when(mSubControllerMock).getActiveSubscriptionInfoList(anyString());
+        doReturn(new int[]{1, 3}).when(mSubControllerMock).getActiveSubIdList(anyBoolean());
+
+        // Nothing should happen until carrier config change is notified on sub 3.
+        mMultiSimSettingControllerUT.notifySubscriptionInfoChanged();
+        waitABit();
+        verify(mContext, never()).sendBroadcast(any());
+
+        mMultiSimSettingControllerUT.notifyCarrierConfigChanged(1, 3);
+        waitABit();
+        // Intent should be broadcast to ask default data selection.
+        Intent intent = captureBroadcastIntent();
+        assertEquals(ACTION_PRIMARY_SUBSCRIPTION_LIST_CHANGED, intent.getAction());
+        assertEquals(EXTRA_DEFAULT_SUBSCRIPTION_SELECT_TYPE_DATA,
+                intent.getIntExtra(EXTRA_DEFAULT_SUBSCRIPTION_SELECT_TYPE, -1));
+    }
 }