diff --git a/src/com/android/phone/CarrierConfigLoader.java b/src/com/android/phone/CarrierConfigLoader.java
index d944fa0..69f29bd 100644
--- a/src/com/android/phone/CarrierConfigLoader.java
+++ b/src/com/android/phone/CarrierConfigLoader.java
@@ -813,10 +813,10 @@
                 Intent.FLAG_RECEIVER_FOREGROUND);
         if (addSubIdExtra) {
             int simApplicationState = TelephonyManager.SIM_STATE_UNKNOWN;
-            int[] subIds = SubscriptionManager.getSubId(phoneId);
-            if (!ArrayUtils.isEmpty(subIds)) {
+            int subId = SubscriptionManager.getSubscriptionId(phoneId);
+            if (SubscriptionManager.isValidSubscriptionId(subId)) {
                 TelephonyManager telMgr = TelephonyManager.from(mContext)
-                        .createForSubscriptionId(subIds[0]);
+                        .createForSubscriptionId(subId);
                 simApplicationState = telMgr.getSimApplicationState();
             }
             logd("Broadcast CARRIER_CONFIG_CHANGED for phone " + phoneId
@@ -834,9 +834,9 @@
         intent.putExtra(CarrierConfigManager.EXTRA_REBROADCAST_ON_UNLOCK,
                 mFromSystemUnlocked[phoneId]);
         mContext.sendBroadcastAsUser(intent, UserHandle.ALL);
-        int[] subIds = SubscriptionManager.getSubId(phoneId);
-        if (subIds != null && subIds.length > 0) {
-            logd("Broadcast CARRIER_CONFIG_CHANGED for phone " + phoneId + ", subId=" + subIds[0]);
+        int subId = SubscriptionManager.getSubscriptionId(phoneId);
+        if (SubscriptionManager.isValidSubscriptionId(subId)) {
+            logd("Broadcast CARRIER_CONFIG_CHANGED for phone " + phoneId + ", subId=" + subId);
         } else {
             logd("Broadcast CARRIER_CONFIG_CHANGED for phone " + phoneId);
         }
@@ -1730,12 +1730,12 @@
     }
 
     private boolean hasCarrierPrivileges(@NonNull String pkgName, int phoneId) {
-        int[] subIds = SubscriptionManager.getSubId(phoneId);
-        if (ArrayUtils.isEmpty(subIds)) {
+        int subId = SubscriptionManager.getSubscriptionId(phoneId);
+        if (!SubscriptionManager.isValidSubscriptionId(subId)) {
             return false;
         }
-        return TelephonyManager.from(mContext).createForSubscriptionId(
-                subIds[0]).checkCarrierPrivilegesForPackage(pkgName)
+        return TelephonyManager.from(mContext).createForSubscriptionId(subId)
+                .checkCarrierPrivilegesForPackage(pkgName)
                 == TelephonyManager.CARRIER_PRIVILEGE_STATUS_HAS_ACCESS;
     }
 
diff --git a/src/com/android/phone/ImsUtil.java b/src/com/android/phone/ImsUtil.java
index ba4ad38..d90c256 100644
--- a/src/com/android/phone/ImsUtil.java
+++ b/src/com/android/phone/ImsUtil.java
@@ -154,12 +154,7 @@
     }
 
     private static int getSubId(int phoneId) {
-        final int[] subIds = SubscriptionManager.getSubId(phoneId);
-        int subId = SubscriptionManager.INVALID_SUBSCRIPTION_ID;
-        if (subIds != null && subIds.length >= 1) {
-            subId = subIds[0];
-        }
-        return subId;
+        return SubscriptionManager.getSubscriptionId(phoneId);
     }
 
     private static boolean getLastKnownRoamingState(int phoneId) {
diff --git a/src/com/android/phone/PhoneInterfaceManager.java b/src/com/android/phone/PhoneInterfaceManager.java
index b91ec7c..0dd316f 100644
--- a/src/com/android/phone/PhoneInterfaceManager.java
+++ b/src/com/android/phone/PhoneInterfaceManager.java
@@ -5813,11 +5813,9 @@
      */
     public boolean setBoundImsServiceOverride(int slotIndex, boolean isCarrierService,
             int[] featureTypes, String packageName) {
-        int[] subIds = SubscriptionManager.getSubId(slotIndex);
         TelephonyPermissions.enforceShellOnly(Binder.getCallingUid(), "setBoundImsServiceOverride");
         TelephonyPermissions.enforceCallingOrSelfModifyPermissionOrCarrierPrivilege(mApp,
-                (subIds != null ? subIds[0] : SubscriptionManager.INVALID_SUBSCRIPTION_ID),
-                "setBoundImsServiceOverride");
+                SubscriptionManager.getSubscriptionId(slotIndex), "setBoundImsServiceOverride");
 
         final long identity = Binder.clearCallingIdentity();
         try {
@@ -5847,12 +5845,10 @@
      */
     @Override
     public boolean clearCarrierImsServiceOverride(int slotIndex) {
-        int[] subIds = SubscriptionManager.getSubId(slotIndex);
         TelephonyPermissions.enforceShellOnly(Binder.getCallingUid(),
                 "clearCarrierImsServiceOverride");
         TelephonyPermissions.enforceCallingOrSelfModifyPermissionOrCarrierPrivilege(mApp,
-                (subIds != null ? subIds[0] : SubscriptionManager.INVALID_SUBSCRIPTION_ID),
-                "clearCarrierImsServiceOverride");
+                SubscriptionManager.getSubscriptionId(slotIndex), "clearCarrierImsServiceOverride");
 
         final long identity = Binder.clearCallingIdentity();
         try {
@@ -5877,11 +5873,9 @@
      */
     public String getBoundImsServicePackage(int slotId, boolean isCarrierImsService,
             @ImsFeature.FeatureType int featureType) {
-        int[] subIds = SubscriptionManager.getSubId(slotId);
         TelephonyPermissions
-                .enforceCallingOrSelfReadPrivilegedPhoneStatePermissionOrCarrierPrivilege(
-                mApp, (subIds != null ? subIds[0] : SubscriptionManager.INVALID_SUBSCRIPTION_ID),
-                "getBoundImsServicePackage");
+                .enforceCallingOrSelfReadPrivilegedPhoneStatePermissionOrCarrierPrivilege(mApp,
+                        SubscriptionManager.getSubscriptionId(slotId), "getBoundImsServicePackage");
 
         final long identity = Binder.clearCallingIdentity();
         try {
diff --git a/src/com/android/phone/TelephonyShellCommand.java b/src/com/android/phone/TelephonyShellCommand.java
index 3eb4511..9f86c24 100644
--- a/src/com/android/phone/TelephonyShellCommand.java
+++ b/src/com/android/phone/TelephonyShellCommand.java
@@ -1060,7 +1060,7 @@
     private int handleBarringSendCommand() {
         PrintWriter errPw = getErrPrintWriter();
         int slotId = getDefaultSlot();
-        int subId = SubscriptionManager.getSubId(slotId)[0];
+        int subId = SubscriptionManager.getSubscriptionId(slotId);
         @BarringInfo.BarringServiceInfo.BarringType int barringType =
                 BarringInfo.BarringServiceInfo.BARRING_TYPE_UNCONDITIONAL;
         boolean isConditionallyBarred = false;
@@ -1072,7 +1072,7 @@
                 case "-s": {
                     try {
                         slotId = Integer.parseInt(getNextArgRequired());
-                        subId = SubscriptionManager.getSubId(slotId)[0];
+                        subId = SubscriptionManager.getSubscriptionId(slotId);
                     } catch (NumberFormatException e) {
                         errPw.println("barring send requires an integer as a SLOT_ID.");
                         return -1;
@@ -2123,8 +2123,7 @@
                 return SubscriptionManager.INVALID_SUBSCRIPTION_ID;
             }
         }
-        int[] subIds = SubscriptionManager.getSubId(slotId);
-        return subIds[0];
+        return SubscriptionManager.getSubscriptionId(slotId);
     }
 
     private int handleGbaSetServiceCommand() {
diff --git a/src/com/android/phone/settings/RadioInfo.java b/src/com/android/phone/settings/RadioInfo.java
index 3840999..3cf0c93 100644
--- a/src/com/android/phone/settings/RadioInfo.java
+++ b/src/com/android/phone/settings/RadioInfo.java
@@ -1875,14 +1875,8 @@
                     return;
                 }
                 // getSubId says it takes a slotIndex, but it actually takes a phone index
-                int subId = SubscriptionManager.INVALID_SUBSCRIPTION_ID;
-                int[] subIds = SubscriptionManager.getSubId(phoneIndex);
-                if (subIds != null && subIds.length > 0) {
-                    subId = subIds[0];
-                }
                 mSelectedPhoneIndex = phoneIndex;
-
-                updatePhoneIndex(phoneIndex, subId);
+                updatePhoneIndex(phoneIndex, SubscriptionManager.getSubscriptionId(phoneIndex));
             }
         }