diff --git a/lib/data/services/iperf3_binary_path_provider.dart b/lib/data/services/iperf3_binary_path_provider.dart
index 9bb9baf..1939bc9 100644
--- a/lib/data/services/iperf3_binary_path_provider.dart
+++ b/lib/data/services/iperf3_binary_path_provider.dart
@@ -30,8 +30,11 @@ class Iperf3BinaryPathProvider {
     final file = File('${binaryDir.path}/iperf3');
     await file.writeAsBytes(bytes.buffer.asUint8List());
 
-    // chmod +x the binary
-    await Process.run('chmod', ['+x', file.path]);
+    // chmod +x the binary — /system/bin/sh is always present on Android
+    await Process.run(
+      '/system/bin/sh',
+      ['-c', 'chmod +x "\$1"', '_', file.path],
+    );
 
     _cachedPath = file.path;
   }