diff --git a/android/src/main/java/com/pauldemarco/flutterblue/AdvertisementParser.java b/android/src/main/java/com/pauldemarco/flutterblue/AdvertisementParser.java
index b68f79b4..315ffe44 100644
--- a/android/src/main/java/com/pauldemarco/flutterblue/AdvertisementParser.java
+++ b/android/src/main/java/com/pauldemarco/flutterblue/AdvertisementParser.java
@@ -84,7 +84,7 @@ static AdvertisementData parse(byte[] rawData) {
           break;
         }
         case 0x0A: { // Power level.
-          ret.setTxPowerLevel(data.get());
+          ret.setTxPowerLevel(Protos.Int32Value.newBuilder().setValue(data.get()));
           break;
         }
         case 0x16: // Service Data with 16 bit UUID.
@@ -114,9 +114,15 @@ static AdvertisementData parse(byte[] rawData) {
           break;
         }
         case 0xFF: {// Manufacturer specific data.
-          byte[] msd = new byte[length];
-          data.get(msd);
-          ret.setManufacturerData(ByteString.copyFrom(msd));
+          if(length < 2) {
+            throw new ArrayIndexOutOfBoundsException("Not enough data for Manufacturer specific data.");
+          }
+          int manufacturerId = data.getShort();
+          if((length - 2) > 0) {
+            byte[] msd = new byte[length - 2];
+            data.get(msd);
+            ret.putManufacturerData(manufacturerId, ByteString.copyFrom(msd));
+          }
           break;
         }
         default: {
diff --git a/android/src/main/java/com/pauldemarco/flutterblue/FlutterBluePlugin.java b/android/src/main/java/com/pauldemarco/flutterblue/FlutterBluePlugin.java
index bbb43b84..f1db5292 100644
--- a/android/src/main/java/com/pauldemarco/flutterblue/FlutterBluePlugin.java
+++ b/android/src/main/java/com/pauldemarco/flutterblue/FlutterBluePlugin.java
@@ -622,7 +622,7 @@ private ScanCallback getScanCallback21() {
                 public void onScanResult(int callbackType, ScanResult result) {
                     super.onScanResult(callbackType, result);
                     if(scanResultsSink != null) {
-                        Protos.ScanResult scanResult = ProtoMaker.from(result.getDevice(), result.getScanRecord().getBytes(), result.getRssi());
+                        Protos.ScanResult scanResult = ProtoMaker.from(result.getDevice(), result);
                         scanResultsSink.success(scanResult.toByteArray());
                     }
                 }
diff --git a/android/src/main/java/com/pauldemarco/flutterblue/ProtoMaker.java b/android/src/main/java/com/pauldemarco/flutterblue/ProtoMaker.java
index 4f5fda39..1569ce4e 100644
--- a/android/src/main/java/com/pauldemarco/flutterblue/ProtoMaker.java
+++ b/android/src/main/java/com/pauldemarco/flutterblue/ProtoMaker.java
@@ -4,15 +4,26 @@
 
 package com.pauldemarco.flutterblue;
 
+import android.annotation.TargetApi;
 import android.bluetooth.BluetoothDevice;
 import android.bluetooth.BluetoothGatt;
 import android.bluetooth.BluetoothGattCharacteristic;
 import android.bluetooth.BluetoothGattDescriptor;
 import android.bluetooth.BluetoothGattService;
 import android.bluetooth.BluetoothProfile;
+import android.bluetooth.le.ScanRecord;
+import android.bluetooth.le.ScanResult;
+import android.os.Build;
+import android.os.Parcel;
+import android.os.ParcelUuid;
+import android.util.Log;
+import android.util.SparseArray;
 
 import com.google.protobuf.ByteString;
 
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
 import java.util.UUID;
 
 /**
@@ -32,6 +43,56 @@ static Protos.ScanResult from(BluetoothDevice device, byte[] advertisementData,
         return p.build();
     }
 
+    @TargetApi(21)
+    static Protos.ScanResult from(BluetoothDevice device, ScanResult scanResult) {
+        Protos.ScanResult.Builder p = Protos.ScanResult.newBuilder();
+        p.setDevice(from(device));
+        Protos.AdvertisementData.Builder a = Protos.AdvertisementData.newBuilder();
+        ScanRecord scanRecord = scanResult.getScanRecord();
+        if(Build.VERSION.SDK_INT >= 26) {
+            a.setConnectable(scanResult.isConnectable());
+        } else {
+            if(scanRecord != null) {
+                int flags = scanRecord.getAdvertiseFlags();
+                a.setConnectable((flags & 0x2) > 0);
+            }
+        }
+        if(scanRecord != null) {
+            String deviceName = scanRecord.getDeviceName();
+            if(deviceName != null) {
+                a.setLocalName(deviceName);
+            }
+            int txPower = scanRecord.getTxPowerLevel();
+            if(txPower != Integer.MIN_VALUE) {
+                a.setTxPowerLevel(Protos.Int32Value.newBuilder().setValue(txPower));
+            }
+            // Manufacturer Specific Data
+            SparseArray<byte[]> msd = scanRecord.getManufacturerSpecificData();
+            for (int i = 0; i < msd.size(); i++) {
+                int key = msd.keyAt(i);
+                byte[] value = msd.valueAt(i);
+                a.putManufacturerData(key, ByteString.copyFrom(value));
+            }
+            // Service Data
+            Map<ParcelUuid, byte[]> serviceData = scanRecord.getServiceData();
+            for (Map.Entry<ParcelUuid, byte[]> entry : serviceData.entrySet()) {
+                ParcelUuid key = entry.getKey();
+                byte[] value = entry.getValue();
+                a.putServiceData(key.getUuid().toString(), ByteString.copyFrom(value));
+            }
+            // Service UUIDs
+            List<ParcelUuid> serviceUuids = scanRecord.getServiceUuids();
+            if(serviceUuids != null) {
+                for (ParcelUuid s : serviceUuids) {
+                    a.addServiceUuids(s.getUuid().toString());
+                }
+            }
+        }
+        p.setRssi(scanResult.getRssi());
+        p.setAdvertisementData(a.build());
+        return p.build();
+    }
+
     static Protos.BluetoothDevice from(BluetoothDevice device) {
         Protos.BluetoothDevice.Builder p = Protos.BluetoothDevice.newBuilder();
         p.setRemoteId(device.getAddress());
diff --git a/example/lib/widgets.dart b/example/lib/widgets.dart
index 6b2e9163..74acf750 100644
--- a/example/lib/widgets.dart
+++ b/example/lib/widgets.dart
@@ -25,10 +25,55 @@ class ScanResultTile extends StatelessWidget {
     }
   }
 
+  Widget _buildAdvRow(BuildContext context, String title, String value) {
+    return Padding(
+      padding: const EdgeInsets.symmetric(horizontal: 16.0, vertical: 4.0),
+      child: Row(
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: <Widget>[
+          Text(title, style: Theme.of(context).textTheme.caption),
+          SizedBox(
+            width: 12.0,
+          ),
+          Expanded(
+            child: Text(
+              value,
+              style: Theme.of(context)
+                  .textTheme
+                  .caption
+                  .apply(color: Colors.black),
+              softWrap: true,
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+
+  String getNiceManufacturerData(Map<int, List<int>> data) {
+    if (data.isEmpty) {
+      return null;
+    }
+    List<String> res = [];
+    data.forEach((id, bytes) {
+      res.add('${id.toRadixString(16).toUpperCase()}: $bytes');
+    });
+    return res.join(', ');
+  }
+
+  String getNiceServiceData(Map<String, List<int>> data) {
+    if (data.isEmpty) {
+      return null;
+    }
+    List<String> res = [];
+    data.forEach((id, bytes) {
+      res.add('$id: $bytes');
+    });
+    return res.join(', ');
+  }
+
   @override
   Widget build(BuildContext context) {
-    print('MANU DATA: ${result.advertisementData.manufacturerData}');
-    print('TX POWER: ${result.advertisementData.txPowerLevel}');
     return ExpansionTile(
       title: _buildTitle(context),
       leading: Text(result.rssi.toString()),
@@ -36,15 +81,27 @@ class ScanResultTile extends StatelessWidget {
         child: Text('CONNECT'),
         color: Colors.black,
         textColor: Colors.white,
-        onPressed: onTap,
+        onPressed: (result.advertisementData.connectable) ? onTap : null,
       ),
       children: <Widget>[
-        Row(
-          children: <Widget>[
-            Text('Complete Local Name:'),
-            Text(result.advertisementData.localName)
-          ],
-        )
+        _buildAdvRow(
+            context, 'Complete Local Name', result.advertisementData.localName),
+        _buildAdvRow(context, 'Tx Power Level',
+            '${result.advertisementData.txPowerLevel ?? 'N/A'}'),
+        _buildAdvRow(
+            context,
+            'Manufacturer Data',
+            getNiceManufacturerData(
+                    result.advertisementData.manufacturerData) ??
+                'N/A'),
+        _buildAdvRow(
+            context,
+            'Service UUIDs',
+            (result.advertisementData.serviceUuids.isNotEmpty)
+                ? result.advertisementData.serviceUuids.join(', ')
+                : 'N/A'),
+        _buildAdvRow(context, 'Service Data',
+            getNiceServiceData(result.advertisementData.serviceData) ?? 'N/A'),
       ],
     );
   }
diff --git a/ios/gen/Flutterblue.pbobjc.h b/ios/gen/Flutterblue.pbobjc.h
index b16cb2c1..86df6248 100644
--- a/ios/gen/Flutterblue.pbobjc.h
+++ b/ios/gen/Flutterblue.pbobjc.h
@@ -33,6 +33,7 @@ CF_EXTERN_C_BEGIN
 @class ProtosBluetoothDevice;
 @class ProtosBluetoothService;
 @class ProtosCharacteristicProperties;
+@class ProtosInt32Value;
 @class ProtosReadDescriptorRequest;
 @class ProtosWriteCharacteristicRequest;
 @class ProtosWriteDescriptorRequest;
@@ -147,6 +148,24 @@ BOOL ProtosDeviceStateResponse_BluetoothDeviceState_IsValidValue(int32_t value);
 @interface ProtosFlutterblueRoot : GPBRootObject
 @end
 
+#pragma mark - ProtosInt32Value
+
+typedef GPB_ENUM(ProtosInt32Value_FieldNumber) {
+  ProtosInt32Value_FieldNumber_Value = 1,
+};
+
+/**
+ * Wrapper message for `int32`.
+ *
+ * The JSON representation for `Int32Value` is JSON number.
+ **/
+@interface ProtosInt32Value : GPBMessage
+
+/** The int32 value. */
+@property(nonatomic, readwrite) int32_t value;
+
+@end
+
 #pragma mark - ProtosBluetoothState
 
 typedef GPB_ENUM(ProtosBluetoothState_FieldNumber) {
@@ -186,11 +205,16 @@ typedef GPB_ENUM(ProtosAdvertisementData_FieldNumber) {
 
 @property(nonatomic, readwrite, copy, null_resettable) NSString *localName;
 
-@property(nonatomic, readwrite) int32_t txPowerLevel;
+@property(nonatomic, readwrite, strong, null_resettable) ProtosInt32Value *txPowerLevel;
+/** Test to see if @c txPowerLevel has been set. */
+@property(nonatomic, readwrite) BOOL hasTxPowerLevel;
 
 @property(nonatomic, readwrite) BOOL connectable;
 
-@property(nonatomic, readwrite, copy, null_resettable) NSData *manufacturerData;
+/** Map of manufacturers to their data */
+@property(nonatomic, readwrite, strong, null_resettable) GPBInt32ObjectDictionary<NSData*> *manufacturerData;
+/** The number of items in @c manufacturerData without causing the array to be created. */
+@property(nonatomic, readonly) NSUInteger manufacturerData_Count;
 
 /** Map of service UUIDs to their data. */
 @property(nonatomic, readwrite, strong, null_resettable) NSMutableDictionary<NSString*, NSData*> *serviceData;
diff --git a/ios/gen/Flutterblue.pbobjc.m b/ios/gen/Flutterblue.pbobjc.m
index 386fc25f..efe85579 100644
--- a/ios/gen/Flutterblue.pbobjc.m
+++ b/ios/gen/Flutterblue.pbobjc.m
@@ -45,6 +45,49 @@ @implementation ProtosFlutterblueRoot
   return descriptor;
 }
 
+#pragma mark - ProtosInt32Value
+
+@implementation ProtosInt32Value
+
+@dynamic value;
+
+typedef struct ProtosInt32Value__storage_ {
+  uint32_t _has_storage_[1];
+  int32_t value;
+} ProtosInt32Value__storage_;
+
+// This method is threadsafe because it is initially called
+// in +initialize for each subclass.
++ (GPBDescriptor *)descriptor {
+  static GPBDescriptor *descriptor = nil;
+  if (!descriptor) {
+    static GPBMessageFieldDescription fields[] = {
+      {
+        .name = "value",
+        .dataTypeSpecific.className = NULL,
+        .number = ProtosInt32Value_FieldNumber_Value,
+        .hasIndex = 0,
+        .offset = (uint32_t)offsetof(ProtosInt32Value__storage_, value),
+        .flags = GPBFieldOptional,
+        .dataType = GPBDataTypeInt32,
+      },
+    };
+    GPBDescriptor *localDescriptor =
+        [GPBDescriptor allocDescriptorForClass:[ProtosInt32Value class]
+                                     rootClass:[ProtosFlutterblueRoot class]
+                                          file:ProtosFlutterblueRoot_FileDescriptor()
+                                        fields:fields
+                                    fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
+                                   storageSize:sizeof(ProtosInt32Value__storage_)
+                                         flags:GPBDescriptorInitializationFlag_None];
+    NSAssert(descriptor == nil, @"Startup recursed!");
+    descriptor = localDescriptor;
+  }
+  return descriptor;
+}
+
+@end
+
 #pragma mark - ProtosBluetoothState
 
 @implementation ProtosBluetoothState
@@ -151,17 +194,17 @@ BOOL ProtosBluetoothState_State_IsValidValue(int32_t value__) {
 @implementation ProtosAdvertisementData
 
 @dynamic localName;
-@dynamic txPowerLevel;
+@dynamic hasTxPowerLevel, txPowerLevel;
 @dynamic connectable;
-@dynamic manufacturerData;
+@dynamic manufacturerData, manufacturerData_Count;
 @dynamic serviceData, serviceData_Count;
 @dynamic serviceUuidsArray, serviceUuidsArray_Count;
 
 typedef struct ProtosAdvertisementData__storage_ {
   uint32_t _has_storage_[1];
-  int32_t txPowerLevel;
   NSString *localName;
-  NSData *manufacturerData;
+  ProtosInt32Value *txPowerLevel;
+  GPBInt32ObjectDictionary *manufacturerData;
   NSMutableDictionary *serviceData;
   NSMutableArray *serviceUuidsArray;
 } ProtosAdvertisementData__storage_;
@@ -183,12 +226,12 @@ + (GPBDescriptor *)descriptor {
       },
       {
         .name = "txPowerLevel",
-        .dataTypeSpecific.className = NULL,
+        .dataTypeSpecific.className = GPBStringifySymbol(ProtosInt32Value),
         .number = ProtosAdvertisementData_FieldNumber_TxPowerLevel,
         .hasIndex = 1,
         .offset = (uint32_t)offsetof(ProtosAdvertisementData__storage_, txPowerLevel),
         .flags = GPBFieldOptional,
-        .dataType = GPBDataTypeInt32,
+        .dataType = GPBDataTypeMessage,
       },
       {
         .name = "connectable",
@@ -203,9 +246,9 @@ + (GPBDescriptor *)descriptor {
         .name = "manufacturerData",
         .dataTypeSpecific.className = NULL,
         .number = ProtosAdvertisementData_FieldNumber_ManufacturerData,
-        .hasIndex = 4,
+        .hasIndex = GPBNoHasBit,
         .offset = (uint32_t)offsetof(ProtosAdvertisementData__storage_, manufacturerData),
-        .flags = GPBFieldOptional,
+        .flags = GPBFieldMapKeyInt32,
         .dataType = GPBDataTypeBytes,
       },
       {
diff --git a/lib/gen/flutterblue.pb.dart b/lib/gen/flutterblue.pb.dart
index bee8c92d..d9e8af40 100644
--- a/lib/gen/flutterblue.pb.dart
+++ b/lib/gen/flutterblue.pb.dart
@@ -12,6 +12,36 @@ import 'flutterblue.pbenum.dart';
 
 export 'flutterblue.pbenum.dart';
 
+class Int32Value extends GeneratedMessage {
+  static final BuilderInfo _i = new BuilderInfo('Int32Value')
+    ..a<int>(1, 'value', PbFieldType.O3)
+    ..hasRequiredFields = false
+  ;
+
+  Int32Value() : super();
+  Int32Value.fromBuffer(List<int> i, [ExtensionRegistry r = ExtensionRegistry.EMPTY]) : super.fromBuffer(i, r);
+  Int32Value.fromJson(String i, [ExtensionRegistry r = ExtensionRegistry.EMPTY]) : super.fromJson(i, r);
+  Int32Value clone() => new Int32Value()..mergeFromMessage(this);
+  BuilderInfo get info_ => _i;
+  static Int32Value create() => new Int32Value();
+  static PbList<Int32Value> createRepeated() => new PbList<Int32Value>();
+  static Int32Value getDefault() {
+    if (_defaultInstance == null) _defaultInstance = new _ReadonlyInt32Value();
+    return _defaultInstance;
+  }
+  static Int32Value _defaultInstance;
+  static void $checkItem(Int32Value v) {
+    if (v is! Int32Value) checkItemFailed(v, 'Int32Value');
+  }
+
+  int get value => $_get(0, 0);
+  set value(int v) { $_setSignedInt32(0, v); }
+  bool hasValue() => $_has(0);
+  void clearValue() => clearField(1);
+}
+
+class _ReadonlyInt32Value extends Int32Value with ReadonlyMessageMixin {}
+
 class BluetoothState extends GeneratedMessage {
   static final BuilderInfo _i = new BuilderInfo('BluetoothState')
     ..e<BluetoothState_State>(1, 'state', PbFieldType.OE, BluetoothState_State.UNKNOWN, BluetoothState_State.valueOf, BluetoothState_State.values)
@@ -42,6 +72,42 @@ class BluetoothState extends GeneratedMessage {
 
 class _ReadonlyBluetoothState extends BluetoothState with ReadonlyMessageMixin {}
 
+class AdvertisementData_ManufacturerDataEntry extends GeneratedMessage {
+  static final BuilderInfo _i = new BuilderInfo('AdvertisementData_ManufacturerDataEntry')
+    ..a<int>(1, 'key', PbFieldType.O3)
+    ..a<List<int>>(2, 'value', PbFieldType.OY)
+    ..hasRequiredFields = false
+  ;
+
+  AdvertisementData_ManufacturerDataEntry() : super();
+  AdvertisementData_ManufacturerDataEntry.fromBuffer(List<int> i, [ExtensionRegistry r = ExtensionRegistry.EMPTY]) : super.fromBuffer(i, r);
+  AdvertisementData_ManufacturerDataEntry.fromJson(String i, [ExtensionRegistry r = ExtensionRegistry.EMPTY]) : super.fromJson(i, r);
+  AdvertisementData_ManufacturerDataEntry clone() => new AdvertisementData_ManufacturerDataEntry()..mergeFromMessage(this);
+  BuilderInfo get info_ => _i;
+  static AdvertisementData_ManufacturerDataEntry create() => new AdvertisementData_ManufacturerDataEntry();
+  static PbList<AdvertisementData_ManufacturerDataEntry> createRepeated() => new PbList<AdvertisementData_ManufacturerDataEntry>();
+  static AdvertisementData_ManufacturerDataEntry getDefault() {
+    if (_defaultInstance == null) _defaultInstance = new _ReadonlyAdvertisementData_ManufacturerDataEntry();
+    return _defaultInstance;
+  }
+  static AdvertisementData_ManufacturerDataEntry _defaultInstance;
+  static void $checkItem(AdvertisementData_ManufacturerDataEntry v) {
+    if (v is! AdvertisementData_ManufacturerDataEntry) checkItemFailed(v, 'AdvertisementData_ManufacturerDataEntry');
+  }
+
+  int get key => $_get(0, 0);
+  set key(int v) { $_setSignedInt32(0, v); }
+  bool hasKey() => $_has(0);
+  void clearKey() => clearField(1);
+
+  List<int> get value => $_getN(1);
+  set value(List<int> v) { $_setBytes(1, v); }
+  bool hasValue() => $_has(1);
+  void clearValue() => clearField(2);
+}
+
+class _ReadonlyAdvertisementData_ManufacturerDataEntry extends AdvertisementData_ManufacturerDataEntry with ReadonlyMessageMixin {}
+
 class AdvertisementData_ServiceDataEntry extends GeneratedMessage {
   static final BuilderInfo _i = new BuilderInfo('AdvertisementData_ServiceDataEntry')
     ..aOS(1, 'key')
@@ -81,9 +147,9 @@ class _ReadonlyAdvertisementData_ServiceDataEntry extends AdvertisementData_Serv
 class AdvertisementData extends GeneratedMessage {
   static final BuilderInfo _i = new BuilderInfo('AdvertisementData')
     ..aOS(1, 'localName')
-    ..a<int>(2, 'txPowerLevel', PbFieldType.O3)
+    ..a<Int32Value>(2, 'txPowerLevel', PbFieldType.OM, Int32Value.getDefault, Int32Value.create)
     ..aOB(3, 'connectable')
-    ..a<List<int>>(4, 'manufacturerData', PbFieldType.OY)
+    ..pp<AdvertisementData_ManufacturerDataEntry>(4, 'manufacturerData', PbFieldType.PM, AdvertisementData_ManufacturerDataEntry.$checkItem, AdvertisementData_ManufacturerDataEntry.create)
     ..pp<AdvertisementData_ServiceDataEntry>(5, 'serviceData', PbFieldType.PM, AdvertisementData_ServiceDataEntry.$checkItem, AdvertisementData_ServiceDataEntry.create)
     ..pPS(6, 'serviceUuids')
     ..hasRequiredFields = false
@@ -110,8 +176,8 @@ class AdvertisementData extends GeneratedMessage {
   bool hasLocalName() => $_has(0);
   void clearLocalName() => clearField(1);
 
-  int get txPowerLevel => $_get(1, 0);
-  set txPowerLevel(int v) { $_setSignedInt32(1, v); }
+  Int32Value get txPowerLevel => $_getN(1);
+  set txPowerLevel(Int32Value v) { setField(2, v); }
   bool hasTxPowerLevel() => $_has(1);
   void clearTxPowerLevel() => clearField(2);
 
@@ -120,10 +186,7 @@ class AdvertisementData extends GeneratedMessage {
   bool hasConnectable() => $_has(2);
   void clearConnectable() => clearField(3);
 
-  List<int> get manufacturerData => $_getN(3);
-  set manufacturerData(List<int> v) { $_setBytes(3, v); }
-  bool hasManufacturerData() => $_has(3);
-  void clearManufacturerData() => clearField(4);
+  List<AdvertisementData_ManufacturerDataEntry> get manufacturerData => $_getList(3);
 
   List<AdvertisementData_ServiceDataEntry> get serviceData => $_getList(4);
 
diff --git a/lib/gen/flutterblue.pbjson.dart b/lib/gen/flutterblue.pbjson.dart
index ea86f605..7ed1b045 100644
--- a/lib/gen/flutterblue.pbjson.dart
+++ b/lib/gen/flutterblue.pbjson.dart
@@ -3,6 +3,13 @@
 ///
 // ignore_for_file: non_constant_identifier_names,library_prefixes
 
+const Int32Value$json = const {
+  '1': 'Int32Value',
+  '2': const [
+    const {'1': 'value', '3': 1, '4': 1, '5': 5, '10': 'value'},
+  ],
+};
+
 const BluetoothState$json = const {
   '1': 'BluetoothState',
   '2': const [
@@ -28,13 +35,22 @@ const AdvertisementData$json = const {
   '1': 'AdvertisementData',
   '2': const [
     const {'1': 'local_name', '3': 1, '4': 1, '5': 9, '10': 'localName'},
-    const {'1': 'tx_power_level', '3': 2, '4': 1, '5': 5, '10': 'txPowerLevel'},
+    const {'1': 'tx_power_level', '3': 2, '4': 1, '5': 11, '6': '.Int32Value', '10': 'txPowerLevel'},
     const {'1': 'connectable', '3': 3, '4': 1, '5': 8, '10': 'connectable'},
-    const {'1': 'manufacturer_data', '3': 4, '4': 1, '5': 12, '10': 'manufacturerData'},
+    const {'1': 'manufacturer_data', '3': 4, '4': 3, '5': 11, '6': '.AdvertisementData.ManufacturerDataEntry', '10': 'manufacturerData'},
     const {'1': 'service_data', '3': 5, '4': 3, '5': 11, '6': '.AdvertisementData.ServiceDataEntry', '10': 'serviceData'},
     const {'1': 'service_uuids', '3': 6, '4': 3, '5': 9, '10': 'serviceUuids'},
   ],
-  '3': const [AdvertisementData_ServiceDataEntry$json],
+  '3': const [AdvertisementData_ManufacturerDataEntry$json, AdvertisementData_ServiceDataEntry$json],
+};
+
+const AdvertisementData_ManufacturerDataEntry$json = const {
+  '1': 'ManufacturerDataEntry',
+  '2': const [
+    const {'1': 'key', '3': 1, '4': 1, '5': 5, '10': 'key'},
+    const {'1': 'value', '3': 2, '4': 1, '5': 12, '10': 'value'},
+  ],
+  '7': const {'7': true},
 };
 
 const AdvertisementData_ServiceDataEntry$json = const {
diff --git a/lib/src/flutter_blue.dart b/lib/src/flutter_blue.dart
index 4015845c..bfab991a 100644
--- a/lib/src/flutter_blue.dart
+++ b/lib/src/flutter_blue.dart
@@ -66,7 +66,7 @@ class FlutterBlue {
     StreamController controller;
     controller = new StreamController(
       onListen: () {
-        if(timeout != null) {
+        if (timeout != null) {
           new Future.delayed(timeout, () => controller.close());
         }
       },
@@ -106,8 +106,9 @@ class FlutterBlue {
     StreamController controller;
     controller = new StreamController<BluetoothDeviceState>(
       onListen: () {
-        if(timeout != null) {
-          new Future.delayed(timeout, () => (!connected) ? controller.close(): null);
+        if (timeout != null) {
+          new Future.delayed(
+              timeout, () => (!connected) ? controller.close() : null);
         }
       },
       onCancel: () {
@@ -119,22 +120,23 @@ class FlutterBlue {
     await _channel.invokeMethod('connect', request.writeToBuffer());
 
     subscription = device.onStateChanged().listen(
-        (data) {
-          if(data == BluetoothDeviceState.connected) {
-            print('connected!');
-            connected = true;
-          }
-          controller.add(data);
-        },
-          onError: controller.addError,
-          onDone: controller.close,
-        );
+      (data) {
+        if (data == BluetoothDeviceState.connected) {
+          print('connected!');
+          connected = true;
+        }
+        controller.add(data);
+      },
+      onError: controller.addError,
+      onDone: controller.close,
+    );
 
     yield* controller.stream;
   }
 
   /// Cancels connection to the Bluetooth Device
-  Future _cancelConnection(BluetoothDevice device) => _channel.invokeMethod('disconnect', device.id.toString());
+  Future _cancelConnection(BluetoothDevice device) =>
+      _channel.invokeMethod('disconnect', device.id.toString());
 }
 
 /// State of the bluetooth adapter.
@@ -188,23 +190,28 @@ class ScanResult {
 
 class AdvertisementData {
   final String localName;
-  final List<int> manufacturerData;
-  final Map<String, List<int>> serviceData;
   final int txPowerLevel;
   final bool connectable;
+  final Map<int, List<int>> manufacturerData;
+  final Map<String, List<int>> serviceData;
+  final List<String> serviceUuids;
 
   AdvertisementData(
       {this.localName,
+      this.txPowerLevel,
+      this.connectable,
       this.manufacturerData,
       this.serviceData,
-      this.txPowerLevel,
-      this.connectable});
+      this.serviceUuids});
 
   AdvertisementData.fromProto(protos.AdvertisementData p)
       : localName = p.localName,
-        manufacturerData = p.manufacturerData,
+        txPowerLevel =
+            (p.txPowerLevel.hasValue()) ? p.txPowerLevel.value : null,
+        connectable = p.connectable,
+        manufacturerData = new Map.fromIterable(p.manufacturerData,
+            key: (v) => v.key, value: (v) => v.value),
         serviceData = new Map.fromIterable(p.serviceData,
             key: (v) => v.key, value: (v) => v.value),
-        txPowerLevel = p.txPowerLevel,
-        connectable = p.connectable;
+        serviceUuids = p.serviceUuids;
 }
diff --git a/protos/flutterblue.proto b/protos/flutterblue.proto
index ce348989..fe95a34b 100644
--- a/protos/flutterblue.proto
+++ b/protos/flutterblue.proto
@@ -8,6 +8,14 @@ option java_package = "com.pauldemarco.flutterblue";
 option java_outer_classname = "Protos";
 option objc_class_prefix = "Protos";
 
+// Wrapper message for `int32`.
+//
+// Allows for nullability of fields in messages
+message Int32Value {
+  // The int32 value.
+  int32 value = 1;
+}
+
 message BluetoothState {
   enum State {
     UNKNOWN = 0;
@@ -23,9 +31,9 @@ message BluetoothState {
 
 message AdvertisementData {
   string local_name = 1;
-  int32 tx_power_level = 2;
+  Int32Value tx_power_level = 2;
   bool connectable = 3;
-  bytes manufacturer_data = 4;
+  map<int32, bytes> manufacturer_data = 4; // Map of manufacturers to their data
   map<string, bytes> service_data = 5;  // Map of service UUIDs to their data.
   repeated string service_uuids = 6;
 }