diff --git a/app/lib/service/tx/lib/src/send_tx_dart.dart b/app/lib/service/tx/lib/src/send_tx_dart.dart
index 47b4216f5..e63f9531e 100644
--- a/app/lib/service/tx/lib/src/send_tx_dart.dart
+++ b/app/lib/service/tx/lib/src/send_tx_dart.dart
@@ -146,7 +146,7 @@ class EWAuthorApi<P extends Provider> {
         final timestamp = await kusama.query.timestamp.now(at: blockHash);
 
         // ignore: avoid_dynamic_calls
-        final xts = List<String>.from(block['block']['extrinsics'] as List<dynamic>);
+        final xts = (block['block']['extrinsics'] as List<dynamic>).cast<String>();
         final xtIndex = xts.indexWhere((xt) => xtHash(xt) == hash);
 
         if (xtIndex != -1) {