diff --git a/src/java/com/android/internal/telephony/IccPhoneBookInterfaceManager.java b/src/java/com/android/internal/telephony/IccPhoneBookInterfaceManager.java
index 8ac8010..84a9d26 100644
--- a/src/java/com/android/internal/telephony/IccPhoneBookInterfaceManager.java
+++ b/src/java/com/android/internal/telephony/IccPhoneBookInterfaceManager.java
@@ -237,7 +237,7 @@
         Request updateRequest = new Request();
         synchronized (updateRequest) {
             Message response = mBaseHandler.obtainMessage(EVENT_UPDATE_DONE, updateRequest);
-            AdnRecord newAdn = new AdnRecord(newTag, newPhoneNumber);
+            AdnRecord newAdn = new AdnRecord(efid, index, newTag, newPhoneNumber);
             if (mAdnCache != null) {
                 mAdnCache.updateAdnByIndex(efid, newAdn, index, pin2, response);
                 waitForResult(updateRequest);
diff --git a/src/java/com/android/internal/telephony/uicc/AdnRecord.java b/src/java/com/android/internal/telephony/uicc/AdnRecord.java
index e6968ec..7710a06 100644
--- a/src/java/com/android/internal/telephony/uicc/AdnRecord.java
+++ b/src/java/com/android/internal/telephony/uicc/AdnRecord.java
@@ -104,6 +104,45 @@
         }
     };
 
+    /**
+     * Returns the maximum number of characters that supported by the alpha tag for a record with
+     * the specified maximum size.
+     */
+    public static int getMaxAlphaTagBytes(int maxRecordLength) {
+        return Math.max(0, maxRecordLength - FOOTER_SIZE_BYTES);
+    }
+
+    /**
+     * Encodes the alphaTag to a binary representation supported by the SIM.
+     *
+     * <p>This is the same representation as is used for this field in buildAdnString but there
+     * is no restriction on the length.
+     */
+    public static byte[] encodeAlphaTag(String alphaTag) {
+        return !TextUtils.isEmpty(alphaTag) ? GsmAlphabet.stringToGsm8BitPacked(alphaTag)
+                : new byte[0];
+    }
+
+    /**
+     * Decodes an encoded alphaTag from a record or encoded tag.
+     *
+     * <p>This is the same as is used to construct an AdnRecord from byte[]
+     */
+    public static String decodeAlphaTag(byte[] encodedTagOrRecord, int offset, int length) {
+        return IccUtils.adnStringFieldToString(encodedTagOrRecord, offset, length);
+    }
+
+    /**
+     * Returns the maximum number of digits (or other dialable characters) that can be stored in
+     * the phone number.
+     *
+     * <p>Additional length is supported via the ext1 entity file but the current implementation
+     * doesn't support writing of that file so it is not included in this calculation.
+     */
+    public static int getMaxPhoneNumberDigits() {
+        // Multiply by 2 because it is packed BCD encoded (2 digits per byte).
+        return (ADN_DIALING_NUMBER_END - ADN_DIALING_NUMBER_START + 1) * 2;
+    }
 
     //***** Constructor
     @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
@@ -260,8 +299,7 @@
             return null;
         }
 
-        byteTag = !TextUtils.isEmpty(mAlphaTag) ? GsmAlphabet.stringToGsm8BitPacked(mAlphaTag)
-                : new byte[0];
+        byteTag = encodeAlphaTag(mAlphaTag);
 
         if (byteTag.length > footerOffset) {
             Rlog.w(LOG_TAG, "[buildAdnString] Max length of tag is " + footerOffset);
@@ -329,7 +367,7 @@
     private void
     parseRecord(byte[] record) {
         try {
-            mAlphaTag = IccUtils.adnStringFieldToString(
+            mAlphaTag = decodeAlphaTag(
                             record, 0, record.length - FOOTER_SIZE_BYTES);
 
             int footerOffset = record.length - FOOTER_SIZE_BYTES;
diff --git a/src/java/com/android/internal/telephony/uicc/AdnRecordCache.java b/src/java/com/android/internal/telephony/uicc/AdnRecordCache.java
index d86b8c6..21a6e37 100644
--- a/src/java/com/android/internal/telephony/uicc/AdnRecordCache.java
+++ b/src/java/com/android/internal/telephony/uicc/AdnRecordCache.java
@@ -124,7 +124,9 @@
             case EF_FDN: return EF_EXT2;
             case EF_MSISDN: return EF_EXT1;
             case EF_PBR: return 0; // The EF PBR doesn't have an extension record
-            default: return -1;
+            default:
+                // See TS 131.102 4.4.2.1 '4FXX' are entity files from EF PBR
+                return (0x4FFF & efid) == efid ? 0 : -1;
         }
     }
 
diff --git a/tests/telephonytests/src/com/android/internal/telephony/AdnRecordTest.java b/tests/telephonytests/src/com/android/internal/telephony/AdnRecordTest.java
index 3b786b0..8fe809c 100644
--- a/tests/telephonytests/src/com/android/internal/telephony/AdnRecordTest.java
+++ b/tests/telephonytests/src/com/android/internal/telephony/AdnRecordTest.java
@@ -16,19 +16,23 @@
 
 package com.android.internal.telephony;
 
+import static com.google.common.truth.Truth.assertThat;
+
 import android.os.Parcel;
-import java.util.Arrays;
-import junit.framework.TestCase;
 import android.test.suitebuilder.annotation.SmallTest;
 
 import com.android.internal.telephony.uicc.AdnRecord;
 import com.android.internal.telephony.uicc.IccUtils;
 
+import junit.framework.TestCase;
+
+import java.util.Arrays;
+
 /**
  * {@hide}
  */
 public class AdnRecordTest extends TestCase {
-    
+
     @SmallTest
     public void testBasic() throws Exception {
         AdnRecord adn;
@@ -189,6 +193,20 @@
         assertEquals(adn.getNumber(), copy.getNumber());
         assertTrue(Arrays.equals(adn.getEmails(), copy.getEmails()));
     }
+
+    public void testGetMaxAlphaTagBytes() {
+        assertThat(AdnRecord.getMaxAlphaTagBytes(-1)).isEqualTo(0);
+        assertThat(AdnRecord.getMaxAlphaTagBytes(0)).isEqualTo(0);
+        assertThat(AdnRecord.getMaxAlphaTagBytes(5)).isEqualTo(0);
+        assertThat(AdnRecord.getMaxAlphaTagBytes(14)).isEqualTo(0);
+        assertThat(AdnRecord.getMaxAlphaTagBytes(15)).isEqualTo(1);
+        assertThat(AdnRecord.getMaxAlphaTagBytes(25)).isEqualTo(11);
+        assertThat(AdnRecord.getMaxAlphaTagBytes(30)).isEqualTo(16);
+    }
+
+    public void testGetMaxPhoneNumberDigits() {
+        assertThat(AdnRecord.getMaxPhoneNumberDigits()).isEqualTo(20);
+    }
 }