diff --git a/lib/wallets/wallet/wallet_mixin_interfaces/spark_interface.dart b/lib/wallets/wallet/wallet_mixin_interfaces/spark_interface.dart
index fcf753fd6a..bf3e62700a 100644
--- a/lib/wallets/wallet/wallet_mixin_interfaces/spark_interface.dart
+++ b/lib/wallets/wallet/wallet_mixin_interfaces/spark_interface.dart
@@ -4,6 +4,7 @@ import 'dart:isolate';
 import 'dart:math';
 
 import 'package:bitcoindart/bitcoindart.dart' as btc;
+import 'package:bitcoindart/src/utils/script.dart' as bscript;
 import 'package:coinlib_flutter/coinlib_flutter.dart' as coinlib;
 import 'package:decimal/decimal.dart';
 import 'package:flutter/foundation.dart';
@@ -50,6 +51,8 @@ const SPARK_OUT_LIMIT_PER_TX = 16;
 const OP_SPARKMINT = 0xd1;
 const OP_SPARKSMINT = 0xd2;
 const OP_SPARKSPEND = 0xd3;
+const OP_SPARKNAMEID = 0xe1;
+const OP_DROP = 0x75;
 
 /// top level function for use with [compute]
 String _hashTag(String tag) {
@@ -61,6 +64,28 @@ String _hashTag(String tag) {
   return hash;
 }
 
+@visibleForTesting
+Uint8List sparkNameFeeScript({
+  required Uint8List baseScript,
+  required String name,
+  required String sparkAddress,
+}) => Uint8List.fromList([
+  ...baseScript,
+  ...bscript.compile([
+    OP_SPARKNAMEID,
+    Uint8List.fromList(utf8.encode(name)),
+    OP_DROP,
+    Uint8List.fromList(utf8.encode(sparkAddress)),
+    OP_DROP,
+  ]),
+]);
+
+@visibleForTesting
+bool shouldSubtractSparkFeeFromAmount({
+  required bool isSparkNameRegistration,
+  required bool spendsAll,
+}) => !isSparkNameRegistration && spendsAll;
+
 void initSparkLogging(Level level) => libSpark.initSparkLogging(level);
 
 abstract class _SparkIsolate {
@@ -568,7 +593,10 @@ mixin SparkInterface<T extends ElectrumXCurrencyInterface>
       throw Exception("Insufficient Spark balance");
     }
 
-    final bool isSendAll = available == txAmount;
+    final bool isSendAll = shouldSubtractSparkFeeFromAmount(
+      isSparkNameRegistration: txData.sparkNameInfo != null,
+      spendsAll: available == txAmount,
+    );
 
     // prepare coin data for ffi
     final serializedCoins = coins
@@ -693,6 +721,7 @@ mixin SparkInterface<T extends ElectrumXCurrencyInterface>
     final List<InputV2> tempInputs = [];
     final List<OutputV2> tempOutputs = [];
 
+    var sparkNameFeeScriptSizeDelta = 0;
     for (int i = 0; i < (txData.recipients?.length ?? 0); i++) {
       if (txData.recipients![i].amount.raw == BigInt.zero) {
         continue;
@@ -708,10 +737,19 @@ mixin SparkInterface<T extends ElectrumXCurrencyInterface>
         ),
       );
 
-      final scriptPubKey = btc.Address.addressToOutputScript(
+      var scriptPubKey = btc.Address.addressToOutputScript(
         txData.recipients![i].address,
         _bitcoinDartNetwork,
       );
+      if (txData.sparkNameInfo != null) {
+        final baseScript = scriptPubKey;
+        scriptPubKey = sparkNameFeeScript(
+          baseScript: scriptPubKey,
+          name: txData.sparkNameInfo!.name,
+          sparkAddress: txData.sparkNameInfo!.sparkAddress.value,
+        );
+        sparkNameFeeScriptSizeDelta += scriptPubKey.length - baseScript.length;
+      }
       txb.addOutput(
         scriptPubKey,
         recipientsWithFeeSubtracted[i].amount.raw.toInt(),
@@ -816,7 +854,7 @@ mixin SparkInterface<T extends ElectrumXCurrencyInterface>
       txHash: extractedTx.getHash(),
       additionalTxSize: txData.sparkNameInfo == null
           ? 0
-          : noProofNameTxData!.size,
+          : noProofNameTxData!.size + sparkNameFeeScriptSizeDelta,
     ));
 
     for (final outputScript in spend.outputScripts) {
diff --git a/pubspec.lock b/pubspec.lock
index 091d58a6f0..75185759f2 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -1028,9 +1028,9 @@ packages:
     dependency: "direct main"
     description:
       path: "."
-      ref: "4bd84c88e1b2a817a2604ec53030634cc3304bc7"
-      resolved-ref: "4bd84c88e1b2a817a2604ec53030634cc3304bc7"
-      url: "https://github.com/cypherstack/flutter_libsparkmobile.git"
+      ref: "53db5a06a7b7f3df68fe6263f1453f77513bec06"
+      resolved-ref: "53db5a06a7b7f3df68fe6263f1453f77513bec06"
+      url: "https://github.com/firoorg/flutter_libsparkmobile.git"
     source: git
     version: "0.1.0"
   flutter_lints:
diff --git a/scripts/app_config/templates/pubspec.template.yaml b/scripts/app_config/templates/pubspec.template.yaml
index 6764428fac..ead1294072 100644
--- a/scripts/app_config/templates/pubspec.template.yaml
+++ b/scripts/app_config/templates/pubspec.template.yaml
@@ -43,8 +43,8 @@ dependencies:
 # %%ENABLE_FIRO%%
 #  flutter_libsparkmobile:
 #    git:
-#      url: https://github.com/cypherstack/flutter_libsparkmobile.git
-#      ref: 4bd84c88e1b2a817a2604ec53030634cc3304bc7
+#      url: https://github.com/firoorg/flutter_libsparkmobile.git
+#      ref: 53db5a06a7b7f3df68fe6263f1453f77513bec06
 # %%END_ENABLE_FIRO%%
 
 # %%ENABLE_EPIC%%
diff --git a/test/wallets/spark_name_fee_test.dart b/test/wallets/spark_name_fee_test.dart
new file mode 100644
index 0000000000..0608fa9274
--- /dev/null
+++ b/test/wallets/spark_name_fee_test.dart
@@ -0,0 +1,45 @@
+import 'dart:typed_data';
+
+import 'package:flutter_libsparkmobile/flutter_libsparkmobile.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:stackwallet/wallets/wallet/wallet_mixin_interfaces/spark_interface.dart';
+
+void main() {
+  test('Spark Name validation rejects underscores before construction', () {
+    final pattern = RegExp(kNameRegexString);
+    expect(pattern.hasMatch('NAME-FOR.TESTING'), isTrue);
+    expect(pattern.hasMatch('NAME_FOR_TESTING'), isFalse);
+  });
+
+  test('Spark Name fee output includes the name and address tag', () {
+    final baseScript = Uint8List(25);
+    final feeScript = sparkNameFeeScript(
+      baseScript: baseScript,
+      name: 'alice',
+      sparkAddress: List.filled(144, 'a').join(),
+    );
+
+    expect(feeScript.length - baseScript.length, 155);
+    expect(feeScript.length, 180);
+    expect(feeScript[25], OP_SPARKNAMEID);
+    expect(feeScript[32], OP_DROP);
+    expect(feeScript.last, OP_DROP);
+  });
+
+  test('Spark Name payments never have the miner fee subtracted', () {
+    expect(
+      shouldSubtractSparkFeeFromAmount(
+        isSparkNameRegistration: true,
+        spendsAll: true,
+      ),
+      isFalse,
+    );
+    expect(
+      shouldSubtractSparkFeeFromAmount(
+        isSparkNameRegistration: false,
+        spendsAll: true,
+      ),
+      isTrue,
+    );
+  });
+}