diff --git a/packages/flutter_tools/bin/tool_backend.dart b/packages/flutter_tools/bin/tool_backend.dart
index 64253a5..cb3c533 100644
--- a/packages/flutter_tools/bin/tool_backend.dart
+++ b/packages/flutter_tools/bin/tool_backend.dart
@@ -17,6 +17,7 @@
   final String flutterEngine = Platform.environment['FLUTTER_ENGINE'];
   final String localEngine = Platform.environment['LOCAL_ENGINE'];
   final String flutterRoot = Platform.environment['FLUTTER_ROOT'];
+
   Directory.current = projectDirectory;
 
   if (localEngine != null && !localEngine.contains(buildMode)) {
@@ -32,34 +33,22 @@
 ''');
     exit(1);
   }
-  final String flutterExecutable = path.join(
-    flutterRoot, 'bin', Platform.isWindows ? 'flutter.bat' : 'flutter');
 
-  if (targetPlatform == 'linux-x64') {
-    // TODO(jonahwilliams): currently all builds are debug builds. Remove the
-    // hardcoded mode when profile and release support is added.
-    final ProcessResult unpackResult = await Process.run(
-        flutterExecutable,
-        <String>[
-          '--suppress-analytics',
-          '--verbose',
-          if (flutterEngine != null) '--local-engine-src-path=$flutterEngine',
-          if (localEngine != null) '--local-engine=$localEngine',
-          'assemble',
-          '-dTargetPlatform=$targetPlatform',
-          '-dBuildMode=debug',
-          '-dTargetFile=$flutterTarget',
-          '--output=build',
-          'debug_bundle_linux_assets',
-        ]);
-    if (unpackResult.exitCode != 0) {
-      stderr.write(unpackResult.stderr);
+  String cacheDirectory;
+  switch (targetPlatform) {
+    case 'linux-x64':
+      cacheDirectory = 'linux/flutter/ephemeral';
+      break;
+    case 'windows-x64':
+      cacheDirectory = 'windows/flutter/ephemeral';
+      break;
+    default:
+      stderr.write('Unsupported target platform $targetPlatform');
       exit(1);
-    }
-    return;
   }
 
-  const String cacheDirectory = 'windows/flutter/ephemeral';
+  final String flutterExecutable = path.join(
+      flutterRoot, 'bin', Platform.isWindows ? 'flutter.bat' : 'flutter');
   final ProcessResult unpackResult = await Process.run(
     flutterExecutable,
     <String>[
diff --git a/packages/flutter_tools/lib/src/build_system/targets/linux.dart b/packages/flutter_tools/lib/src/build_system/targets/linux.dart
index 4821163..b57ab3b 100644
--- a/packages/flutter_tools/lib/src/build_system/targets/linux.dart
+++ b/packages/flutter_tools/lib/src/build_system/targets/linux.dart
@@ -2,25 +2,18 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:pool/pool.dart';
-
 import '../../artifacts.dart';
-import '../../asset.dart';
 import '../../base/file_system.dart';
 import '../../build_info.dart';
-import '../../devfs.dart';
 import '../../globals.dart';
 import '../build_system.dart';
-import '../exceptions.dart';
-import 'assets.dart';
-import 'dart.dart';
 
 /// Copies the Linux desktop embedding files to the copy directory.
-class UnpackLinuxDebug extends Target {
-  const UnpackLinuxDebug();
+class UnpackLinux extends Target {
+  const UnpackLinux();
 
   @override
-  String get name => 'unpack_linux_debug';
+  String get name => 'unpack_linux';
 
   @override
   List<Source> get inputs => const <Source>[
@@ -30,12 +23,12 @@
 
   @override
   List<Source> get outputs => const <Source>[
-    Source.pattern('{PROJECT_DIR}/linux/flutter/ephemeral/libflutter_linux_glfw.so'),
-    Source.pattern('{PROJECT_DIR}/linux/flutter/ephemeral/flutter_export.h'),
-    Source.pattern('{PROJECT_DIR}/linux/flutter/ephemeral/flutter_messenger.h'),
-    Source.pattern('{PROJECT_DIR}/linux/flutter/ephemeral/flutter_plugin_registrar.h'),
-    Source.pattern('{PROJECT_DIR}/linux/flutter/ephemeral/flutter_glfw.h'),
-    Source.pattern('{PROJECT_DIR}/linux/flutter/ephemeral/icudtl.dat'),
+    Source.pattern('{PROJECT_DIR}/linux/flutter/libflutter_linux_glfw.so'),
+    Source.pattern('{PROJECT_DIR}/linux/flutter/flutter_export.h'),
+    Source.pattern('{PROJECT_DIR}/linux/flutter/flutter_messenger.h'),
+    Source.pattern('{PROJECT_DIR}/linux/flutter/flutter_plugin_registrar.h'),
+    Source.pattern('{PROJECT_DIR}/linux/flutter/flutter_glfw.h'),
+    Source.pattern('{PROJECT_DIR}/linux/flutter/icudtl.dat'),
   ];
 
   @override
@@ -51,7 +44,6 @@
         environment.projectDir.path,
         'linux',
         'flutter',
-        'ephemeral',
         fs.path.relative(input.path, from: basePath),
       );
       final File destinationFile = fs.file(outputPath);
@@ -62,72 +54,3 @@
     }
   }
 }
-
-/// Creates a debug bundle for the Linux desktop target.
-class DebugBundleLinuxAssets extends Target {
-  const DebugBundleLinuxAssets();
-
-  @override
-  String get name => 'debug_bundle_linux_assets';
-
-  @override
-  List<Target> get dependencies => const <Target>[
-    KernelSnapshot(),
-    UnpackLinuxDebug(),
-  ];
-
-  @override
-  List<Source> get inputs => const <Source>[
-    Source.pattern('{BUILD_DIR}/app.dill'),
-    Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/linux.dart'),
-    Source.behavior(AssetOutputBehavior('flutter_assets')),
-  ];
-
-  @override
-  List<Source> get outputs => const <Source>[
-    Source.behavior(AssetOutputBehavior('flutter_assets')),
-    Source.pattern('{OUTPUT_DIR}/flutter_assets/kernel_blob.bin'),
-    Source.pattern('{OUTPUT_DIR}/flutter_assets/AssetManifest.json'),
-    Source.pattern('{OUTPUT_DIR}/flutter_assets/FontManifest.json'),
-    Source.pattern('{OUTPUT_DIR}/flutter_assets/LICENSE'),
-  ];
-
-  @override
-  Future<void> build(Environment environment) async {
-    if (environment.defines[kBuildMode] == null) {
-      throw MissingDefineException(kBuildMode, 'debug_bundle_linux_assets');
-    }
-    final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
-    final Directory outputDirectory = environment.outputDir
-      .childDirectory('flutter_assets');
-    if (!outputDirectory.existsSync()) {
-      outputDirectory.createSync();
-    }
-
-    // Only copy the kernel blob in debug mode.
-    if (buildMode == BuildMode.debug) {
-      environment.buildDir.childFile('app.dill')
-        .copySync(outputDirectory.childFile('kernel_blob.bin').path);
-    }
-
-    final AssetBundle assetBundle = AssetBundleFactory.instance.createBundle();
-    await assetBundle.build();
-    final Pool pool = Pool(kMaxOpenFiles);
-    await Future.wait<void>(
-      assetBundle.entries.entries.map<Future<void>>((MapEntry<String, DevFSContent> entry) async {
-        final PoolResource resource = await pool.request();
-        try {
-          final File file = fs.file(fs.path.join(outputDirectory.path, entry.key));
-          file.parent.createSync(recursive: true);
-          final DevFSContent content = entry.value;
-          if (content is DevFSFileContent && content.file is File) {
-            await (content.file as File).copy(file.path);
-          } else {
-            await file.writeAsBytes(await entry.value.contentsAsBytes());
-          }
-        } finally {
-          resource.release();
-        }
-      }));
-  }
-}
diff --git a/packages/flutter_tools/lib/src/commands/assemble.dart b/packages/flutter_tools/lib/src/commands/assemble.dart
index ee1e72d..c8048cb 100644
--- a/packages/flutter_tools/lib/src/commands/assemble.dart
+++ b/packages/flutter_tools/lib/src/commands/assemble.dart
@@ -20,6 +20,7 @@
 
 /// All currently implemented targets.
 const List<Target> _kDefaultTargets = <Target>[
+  UnpackLinux(),
   UnpackWindows(),
   CopyAssets(),
   KernelSnapshot(),
@@ -31,7 +32,6 @@
   DebugMacOSBundleFlutterAssets(),
   ProfileMacOSBundleFlutterAssets(),
   ReleaseMacOSBundleFlutterAssets(),
-  DebugBundleLinuxAssets(),
   WebReleaseBundle(),
 ];
 
@@ -77,7 +77,7 @@
     final Target result = _kDefaultTargets
         .firstWhere((Target target) => target.name == name, orElse: () => null);
     if (result == null) {
-      throwToolExit('No target named "$name" defined.');
+      throwToolExit('No target named "{target.name} defined."');
     }
     return result;
   }
diff --git a/packages/flutter_tools/lib/src/commands/unpack.dart b/packages/flutter_tools/lib/src/commands/unpack.dart
index 5fd57c0..6dfdc10 100644
--- a/packages/flutter_tools/lib/src/commands/unpack.dart
+++ b/packages/flutter_tools/lib/src/commands/unpack.dart
@@ -5,6 +5,7 @@
 import '../artifacts.dart';
 import '../base/common.dart';
 import '../base/file_system.dart';
+import '../base/process.dart';
 import '../build_info.dart';
 import '../cache.dart';
 import '../globals.dart';
@@ -12,12 +13,26 @@
 
 /// The directory in the Flutter cache for each platform's artifacts.
 const Map<TargetPlatform, String> flutterArtifactPlatformDirectory = <TargetPlatform, String>{
+  TargetPlatform.linux_x64: 'linux-x64',
+  TargetPlatform.darwin_x64: 'darwin-x64',
   TargetPlatform.windows_x64: 'windows-x64',
 };
 
 // TODO(jonahwilliams): this should come from a configuration in each build
 // directory.
 const Map<TargetPlatform, List<String>> artifactFilesByPlatform = <TargetPlatform, List<String>>{
+  TargetPlatform.linux_x64: <String>[
+    'libflutter_linux_glfw.so',
+    'flutter_export.h',
+    'flutter_messenger.h',
+    'flutter_plugin_registrar.h',
+    'flutter_glfw.h',
+    'icudtl.dat',
+    'cpp_client_wrapper_glfw/',
+  ],
+  TargetPlatform.darwin_x64: <String>[
+    'FlutterMacOS.framework',
+  ],
   TargetPlatform.windows_x64: <String>[
     'flutter_windows.dll',
     'flutter_windows.dll.exp',
@@ -37,7 +52,7 @@
   UnpackCommand() {
     argParser.addOption(
       'target-platform',
-      allowed: <String>['windows-x64'],
+      allowed: <String>['darwin-x64', 'linux-x64', 'windows-x64'],
     );
     argParser.addOption('cache-dir',
         help: 'Location to output platform specific artifacts.');
@@ -59,9 +74,15 @@
     };
     final TargetPlatform targetPlatform = getTargetPlatformForName(argResults['target-platform']);
     switch (targetPlatform) {
+      case TargetPlatform.darwin_x64:
+        result.add(DevelopmentArtifact.macOS);
+        break;
       case TargetPlatform.windows_x64:
         result.add(DevelopmentArtifact.windows);
         break;
+      case TargetPlatform.linux_x64:
+        result.add(DevelopmentArtifact.linux);
+        break;
       default:
     }
     return result;
@@ -113,9 +134,15 @@
   bool copyCachedArtifacts(String targetDirectory) {
     String cacheStamp;
     switch (platform) {
+      case TargetPlatform.linux_x64:
+        cacheStamp = 'linux-sdk';
+        break;
       case TargetPlatform.windows_x64:
         cacheStamp = 'windows-sdk';
         break;
+      case TargetPlatform.darwin_x64:
+        cacheStamp = 'macos-sdk';
+        break;
       default:
         throwToolExit('Unsupported target platform: $platform');
     }
@@ -181,17 +208,27 @@
 
     try {
       fs.directory(targetDirectory).createSync(recursive: true);
-      for (final String entityName in artifactFiles) {
-        final String sourcePath = fs.path.join(sourceDirectory, entityName);
-        final String targetPath = fs.path.join(targetDirectory, entityName);
-        if (entityName.endsWith('/')) {
-          copyDirectorySync(
-            fs.directory(sourcePath),
-            fs.directory(targetPath),
-          );
-        } else {
-          fs.file(sourcePath)
-            .copySync(fs.path.join(targetDirectory, entityName));
+
+      // On macOS, delete the existing framework if any before copying in the
+      // new one, since it's a directory. On the other platforms, where files
+      // are just individual files, this isn't necessary since copying over
+      // existing files will do the right thing.
+      if (platform == TargetPlatform.darwin_x64) {
+        _copyMacOSFramework(
+            fs.path.join(sourceDirectory, artifactFiles[0]), targetDirectory);
+      } else {
+        for (final String entityName in artifactFiles) {
+          final String sourcePath = fs.path.join(sourceDirectory, entityName);
+          final String targetPath = fs.path.join(targetDirectory, entityName);
+          if (entityName.endsWith('/')) {
+            copyDirectorySync(
+              fs.directory(sourcePath),
+              fs.directory(targetPath),
+            );
+          } else {
+            fs.file(sourcePath)
+              .copySync(fs.path.join(targetDirectory, entityName));
+          }
         }
       }
 
@@ -233,6 +270,43 @@
     _lastCopiedHashFile(directory).writeAsStringSync(hash);
   }
 
+  /// Copies the framework at [frameworkPath] to [targetDirectory]
+  /// by invoking 'cp -R'.
+  ///
+  /// The shelling out is done to avoid complications with preserving special
+  /// files (e.g., symbolic links) in the framework structure.
+  ///
+  /// Removes any previous version of the framework that already exists in the
+  /// target directory.
+  void _copyMacOSFramework(String frameworkPath, String targetDirectory) {
+    _deleteFrameworkIfPresent(
+        fs.path.join(targetDirectory, fs.path.basename(frameworkPath)));
+
+    final RunResult result = processUtils
+        .runSync(<String>['cp', '-R', frameworkPath, targetDirectory]);
+    if (result.exitCode != 0) {
+      throw Exception(
+        'Failed to copy framework (exit ${result.exitCode}:\n'
+        '${result.stdout}\n---\n${result.stderr}',
+      );
+    }
+  }
+
+  /// Recursively deletes the framework at [frameworkPath], if it exists.
+  void _deleteFrameworkIfPresent(String frameworkPath) {
+    // Ensure that the path is a framework, to minimize the potential for
+    // catastrophic deletion bugs with bad arguments.
+    if (fs.path.extension(frameworkPath) != '.framework') {
+      throw Exception(
+          'Attempted to delete a non-framework directory: $frameworkPath');
+    }
+
+    final Directory directory = fs.directory(frameworkPath);
+    if (directory.existsSync()) {
+      directory.deleteSync(recursive: true);
+    }
+  }
+
   /// Returns the engine hash from [file] as a String, or null.
   ///
   /// If the file is missing, or cannot be read, returns null.
diff --git a/packages/flutter_tools/test/general.shard/build_system/targets/linux_test.dart b/packages/flutter_tools/test/general.shard/build_system/targets/linux_test.dart
index d707235..6f6bcbf 100644
--- a/packages/flutter_tools/test/general.shard/build_system/targets/linux_test.dart
+++ b/packages/flutter_tools/test/general.shard/build_system/targets/linux_test.dart
@@ -5,7 +5,6 @@
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/platform.dart';
 import 'package:flutter_tools/src/build_system/build_system.dart';
-import 'package:flutter_tools/src/build_system/targets/dart.dart';
 import 'package:flutter_tools/src/build_system/targets/linux.dart';
 import 'package:flutter_tools/src/cache.dart';
 import 'package:mockito/mockito.dart';
@@ -29,15 +28,11 @@
     when(mockPlatform.isWindows).thenReturn(false);
     when(mockPlatform.isMacOS).thenReturn(false);
     when(mockPlatform.isLinux).thenReturn(true);
-    when(mockPlatform.environment).thenReturn(Map<String, String>.unmodifiable(<String, String>{}));
     testbed = Testbed(setup: () {
       Cache.flutterRoot = '';
       environment = Environment(
         outputDir: fs.currentDirectory,
         projectDir: fs.currentDirectory,
-        defines: <String, String>{
-          kBuildMode: 'debug',
-        }
       );
       fs.file('bin/cache/artifacts/engine/linux-x64/libflutter_linux_glfw.so').createSync(recursive: true);
       fs.file('bin/cache/artifacts/engine/linux-x64/flutter_export.h').createSync();
@@ -54,51 +49,36 @@
   });
 
   test('Copies files to correct cache directory', () => testbed.run(() async {
-    final BuildResult result = await buildSystem.build(const UnpackLinuxDebug(), environment);
+    final BuildResult result = await buildSystem.build(const UnpackLinux(), environment);
 
     expect(result.hasException, false);
-    expect(fs.file('linux/flutter/ephemeral/libflutter_linux_glfw.so').existsSync(), true);
-    expect(fs.file('linux/flutter/ephemeral/flutter_export.h').existsSync(), true);
-    expect(fs.file('linux/flutter/ephemeral/flutter_messenger.h').existsSync(), true);
-    expect(fs.file('linux/flutter/ephemeral/flutter_plugin_registrar.h').existsSync(), true);
-    expect(fs.file('linux/flutter/ephemeral/flutter_glfw.h').existsSync(), true);
-    expect(fs.file('linux/flutter/ephemeral/icudtl.dat').existsSync(), true);
-    expect(fs.file('linux/flutter/ephemeral/cpp_client_wrapper_glfw/foo').existsSync(), true);
+    expect(fs.file('linux/flutter/libflutter_linux_glfw.so').existsSync(), true);
+    expect(fs.file('linux/flutter/flutter_export.h').existsSync(), true);
+    expect(fs.file('linux/flutter/flutter_messenger.h').existsSync(), true);
+    expect(fs.file('linux/flutter/flutter_plugin_registrar.h').existsSync(), true);
+    expect(fs.file('linux/flutter/flutter_glfw.h').existsSync(), true);
+    expect(fs.file('linux/flutter/icudtl.dat').existsSync(), true);
+    expect(fs.file('linux/flutter/cpp_client_wrapper_glfw/foo').existsSync(), true);
   }));
 
   test('Does not re-copy files unecessarily', () => testbed.run(() async {
-    await buildSystem.build(const UnpackLinuxDebug(), environment);
+    await buildSystem.build(const UnpackLinux(), environment);
     // Set a date in the far distant past to deal with the limited resolution
     // of the windows filesystem.
     final DateTime theDistantPast = DateTime(1991, 8, 23);
-    fs.file('linux/flutter/ephemeral/libflutter_linux_glfw.so').setLastModifiedSync(theDistantPast);
-    await buildSystem.build(const UnpackLinuxDebug(), environment);
+    fs.file('linux/flutter/libflutter_linux_glfw.so').setLastModifiedSync(theDistantPast);
+    await buildSystem.build(const UnpackLinux(), environment);
 
-    expect(fs.file('linux/flutter/ephemeral/libflutter_linux_glfw.so').statSync().modified, equals(theDistantPast));
+    expect(fs.file('linux/flutter/libflutter_linux_glfw.so').statSync().modified, equals(theDistantPast));
   }));
 
   test('Detects changes in input cache files', () => testbed.run(() async {
-    await buildSystem.build(const UnpackLinuxDebug(), environment);
+    await buildSystem.build(const UnpackLinux(), environment);
     fs.file('bin/cache/artifacts/engine/linux-x64/libflutter_linux_glfw.so').writeAsStringSync('asd'); // modify cache.
 
-    await buildSystem.build(const UnpackLinuxDebug(), environment);
+    await buildSystem.build(const UnpackLinux(), environment);
 
-    expect(fs.file('linux/flutter/ephemeral/libflutter_linux_glfw.so').readAsStringSync(), 'asd');
-  }));
-
-  test('Copies artifacts to out directory', () => testbed.run(() async {
-    environment.buildDir.createSync(recursive: true);
-
-    // Create input files.
-    environment.buildDir.childFile('app.dill').createSync();
-
-    await const DebugBundleLinuxAssets().build(environment);
-    final Directory output = environment.outputDir
-      .childDirectory('flutter_assets');
-
-    expect(output.childFile('kernel_blob.bin').existsSync(), true);
-    expect(output.childFile('FontManifest.json').existsSync(), false);
-    expect(output.childFile('AssetManifest.json').existsSync(), true);
+    expect(fs.file('linux/flutter/libflutter_linux_glfw.so').readAsStringSync(), 'asd');
   }));
 }