diff --git a/dev/devicelab/bin/tasks/commands_test.dart b/dev/devicelab/bin/tasks/commands_test.dart
index 19d6f64023a..c12b4dbede4 100644
--- a/dev/devicelab/bin/tasks/commands_test.dart
+++ b/dev/devicelab/bin/tasks/commands_test.dart
@@ -26,8 +26,7 @@ void main() {
       print('run: starting...');
       final Process run = await startProcess(
         path.join(flutterDirectory.path, 'bin', 'flutter'),
-         // Fast start is disabled due to https://github.com/flutter/flutter/issues/48971.
-        <String>['run', '--verbose', '--disable-service-auth-codes', '-d', device.deviceId, 'lib/commands.dart', '--no-fast-start'],
+        <String>['run', '--verbose', '--disable-service-auth-codes', '-d', device.deviceId, 'lib/commands.dart'],
       );
       final StreamController<String> stdout = StreamController<String>.broadcast();
       run.stdout
diff --git a/dev/devicelab/bin/tasks/named_isolates_test.dart b/dev/devicelab/bin/tasks/named_isolates_test.dart
index d038d17e755..ff2feb64779 100644
--- a/dev/devicelab/bin/tasks/named_isolates_test.dart
+++ b/dev/devicelab/bin/tasks/named_isolates_test.dart
@@ -25,9 +25,8 @@ void main() {
     section('Compile and run the tester app');
     Completer<void> firstNameFound = Completer<void>();
     Completer<void> secondNameFound = Completer<void>();
-    // Fast start is disabled due to https://github.com/flutter/flutter/issues/48971.
     final Process runProcess = await _run(device: device, command:
-        <String>['run', '--disable-service-auth-codes', '--no-fast-start'], stdoutListener: (String line) {
+        <String>['run', '--disable-service-auth-codes'], stdoutListener: (String line) {
       if (line.contains(_kFirstIsolateName)) {
         firstNameFound.complete();
       } else if (line.contains(_kSecondIsolateName)) {
diff --git a/dev/devicelab/bin/tasks/run_machine_concurrent_hot_reload.dart b/dev/devicelab/bin/tasks/run_machine_concurrent_hot_reload.dart
index f60a2c247c3..80fb3fc638f 100644
--- a/dev/devicelab/bin/tasks/run_machine_concurrent_hot_reload.dart
+++ b/dev/devicelab/bin/tasks/run_machine_concurrent_hot_reload.dart
@@ -48,8 +48,6 @@ void main() {
           'run',
           '--machine',
           '--verbose',
-          // Fast start is disabled due to https://github.com/flutter/flutter/issues/48971.
-          '--no-fast-start',
           '-d',
           device.deviceId,
           'lib/commands.dart',
diff --git a/dev/devicelab/lib/tasks/perf_tests.dart b/dev/devicelab/lib/tasks/perf_tests.dart
index 06f02c6d784..9e9aaf0f418 100644
--- a/dev/devicelab/lib/tasks/perf_tests.dart
+++ b/dev/devicelab/lib/tasks/perf_tests.dart
@@ -719,8 +719,6 @@ class ReportedDurationTest {
       print('launching $project$test on device...');
       await flutter('run', options: <String>[
         '--verbose',
-        // Fast start is disabled due to https://github.com/flutter/flutter/issues/48971.
-        '--no-fast-start',
         '--${_reportedDurationTestToString(flavor)}',
         '--no-resident',
         '-d', device.deviceId,
diff --git a/packages/flutter_tools/lib/src/commands/run.dart b/packages/flutter_tools/lib/src/commands/run.dart
index 10ae7f4e689..006d5210b95 100644
--- a/packages/flutter_tools/lib/src/commands/run.dart
+++ b/packages/flutter_tools/lib/src/commands/run.dart
@@ -189,7 +189,8 @@ class RunCommand extends RunCommandBase {
       )
       ..addFlag('fast-start',
         negatable: true,
-        defaultsTo: true,
+        defaultsTo: false,
+        hide: true,
         help: 'Whether to quickly bootstrap applications with a minimal app. '
               'Currently this is only supported on Android devices. This option '
               'cannot be paired with --use-application-binary.'
@@ -318,6 +319,10 @@ class RunCommand extends RunCommandBase {
       await super.validateCommand();
     }
 
+    if (boolArg('fast-start') && runningWithPrebuiltApplication) {
+      throwToolExit('--fast-start is not supported with --use-application-binary');
+    }
+
     devices = await findAllTargetDevices();
     if (devices == null) {
       throwToolExit(null);
@@ -360,9 +365,7 @@ class RunCommand extends RunCommandBase {
         vmserviceOutFile: stringArg('vmservice-out-file'),
         // Allow forcing fast-start to off to prevent doing more work on devices that
         // don't support it.
-        fastStart: boolArg('fast-start')
-          && !runningWithPrebuiltApplication
-          && devices.every((Device device) => device.supportsFastStart),
+        fastStart: boolArg('fast-start') && devices.every((Device device) => device.supportsFastStart),
       );
     }
   }
@@ -425,6 +428,12 @@ class RunCommand extends RunCommandBase {
     }
 
     for (final Device device in devices) {
+      if (!device.supportsFastStart && boolArg('fast-start')) {
+        globals.printStatus(
+          'Using --fast-start option with device ${device.name}, but this device '
+          'does not support it. Overriding the setting to false.'
+        );
+      }
       if (await device.isLocalEmulator) {
         if (await device.supportsHardwareRendering) {
           final bool enableSoftwareRendering = boolArg('enable-software-rendering') == true;
diff --git a/packages/flutter_tools/test/commands.shard/hermetic/run_test.dart b/packages/flutter_tools/test/commands.shard/hermetic/run_test.dart
index ccf8b2fad57..466f4c8c632 100644
--- a/packages/flutter_tools/test/commands.shard/hermetic/run_test.dart
+++ b/packages/flutter_tools/test/commands.shard/hermetic/run_test.dart
@@ -77,7 +77,7 @@ void main() {
         ]);
         fail('Expect exception');
       } catch (e) {
-        expect(e.toString(), isNot(contains('--fast-start is not supported with --use-application-binary')));
+        expect(e.toString(), contains('--fast-start is not supported with --use-application-binary'));
       }
     }, overrides: <Type, Generator>{
       FileSystem: () => MemoryFileSystem(),
@@ -115,10 +115,10 @@ void main() {
       }
 
       final BufferLogger bufferLogger = globals.logger as BufferLogger;
-      expect(bufferLogger.statusText, isNot(contains(
+      expect(bufferLogger.statusText, contains(
         'Using --fast-start option with device mockdevice, but this device '
         'does not support it. Overriding the setting to false.'
-      )));
+      ));
     }, overrides: <Type, Generator>{
       FileSystem: () => MemoryFileSystem(),
       ProcessManager: () => FakeProcessManager.any(),