diff --git a/src/libraries/Common/src/System/HexConverter.cs b/src/libraries/Common/src/System/HexConverter.cs
index d0cd3f074dc00..836145c73d71f 100644
--- a/src/libraries/Common/src/System/HexConverter.cs
+++ b/src/libraries/Common/src/System/HexConverter.cs
@@ -83,6 +83,7 @@ public static void ToCharsBuffer(byte value, Span<char> buffer, int startingInde
             buffer[startingIndex] = (char)(packedResult >> 8);
         }
 
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static void EncodeToUtf16(ReadOnlySpan<byte> bytes, Span<char> chars, Casing casing = Casing.Upper)
         {
             Debug.Assert(chars.Length >= bytes.Length * 2);
diff --git a/src/libraries/System.Net.NetworkInformation/src/System/Net/NetworkInformation/PhysicalAddress.cs b/src/libraries/System.Net.NetworkInformation/src/System/Net/NetworkInformation/PhysicalAddress.cs
index f2203d56bfe08..ac4cfb0ffcc18 100644
--- a/src/libraries/System.Net.NetworkInformation/src/System/Net/NetworkInformation/PhysicalAddress.cs
+++ b/src/libraries/System.Net.NetworkInformation/src/System/Net/NetworkInformation/PhysicalAddress.cs
@@ -90,7 +90,7 @@ public override bool Equals(object? comparand)
 
         public override string ToString()
         {
-            return Convert.ToHexString(_address.AsSpan());
+            return HexConverter.ToString(_address.AsSpan(), HexConverter.Casing.Upper);
         }
 
         public byte[] GetAddressBytes()