diff --git a/local-cli/bundle/output/unbundle/as-assets.js b/local-cli/bundle/output/unbundle/as-assets.js
new file mode 100644
index 000000000..f4f429c29
--- /dev/null
+++ b/local-cli/bundle/output/unbundle/as-assets.js
@@ -0,0 +1,103 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+'use strict';
+
+const fs = require('fs');
+const mkdirp = require('mkdirp');
+const path = require('path');
+const Promise = require('promise');
+
+const writeFile = require('../writeFile');
+const writeSourceMap = require('./write-sourcemap');
+const MODULES_DIR = 'js-modules';
+
+/**
+ * Saves all JS modules of an app as single files
+ * The startup code (prelude, polyfills etc.) are written to the file
+ * designated by the `bundleOuput` option.
+ * All other modules go into a 'js-modules' folder that in the same parent
+ * directory as the startup file.
+ */
+function saveAsAssets(bundle, options, log) {
+  const {
+    'bundle-output': bundleOutput,
+    'bundle-encoding': encoding,
+    dev,
+    'sourcemap-output': sourcemapOutput,
+  } = options;
+
+  log('start');
+  const {startupCode, modules} = bundle.getUnbundle({minify: !dev});
+  log('finish');
+
+  log('Writing bundle output to:', bundleOutput);
+  const writeUnbundle =
+    Promise.all([
+      writeModules(path.dirname(bundleOutput), modules, encoding),
+      writeStartupFile(bundleOutput, startupCode, encoding)
+    ]);
+  writeUnbundle.then(() => log('Done writing unbundle output'));
+
+  return Promise.all([writeUnbundle, writeSourceMap(sourcemapOutput, '', log)]);
+}
+
+function createDir(dirName) {
+  return new Promise((resolve, reject) =>
+    mkdirp(dirName, error => error ? reject(error) : resolve()));
+}
+
+function createDirectoriesForModules(modulesDir, modules) {
+  const dirNames =
+    modules.map(name => {
+      // get all needed directory names
+      const dir = path.dirname(name);
+      return dir === '.' ? modulesDir : path.join(modulesDir, dir);
+    })
+    .filter(Boolean) // remove empty directories
+    .sort()
+    .filter((dir, i, dirs) => {
+      // remove parent directories. After sorting, parent directories are
+      // located before child directories
+      const next = dirs[i + 1];
+      return !next || next !== dir && !next.startsWith(dir + path.sep);
+    });
+
+  return dirNames.reduce(
+    (promise, dirName) =>
+      promise.then(() => createDir(dirName)), Promise.resolve());
+}
+
+function writeModuleFile(module, modulesDir, encoding) {
+  const {name, code} = module;
+  return writeFile(path.join(modulesDir, name + '.js'), code, encoding);
+}
+
+function writeModuleFiles(modules, modulesDir, encoding) {
+  const writeFiles =
+    modules.map(module => writeModuleFile(module, modulesDir, encoding));
+  return Promise.all(writeFiles);
+}
+
+function writeModules(assetsDest, modules, encoding) {
+  const modulesDir = path.join(assetsDest, MODULES_DIR);
+
+  return (
+    createDirectoriesForModules(modulesDir, modules.map(({name}) => name))
+      .then(() => writeModuleFiles(modules, modulesDir, encoding))
+  );
+}
+
+function writeStartupFile(outputFile, code, encoding) {
+  return new Promise((resolve, reject) => {
+    fs.createWriteStream(outputFile).
+      write(code, encoding, error => error ? reject(error) : resolve());
+  });
+}
+
+module.exports = saveAsAssets;
diff --git a/local-cli/bundle/output/unbundle.js b/local-cli/bundle/output/unbundle/as-indexed-file.js
similarity index 82%
rename from local-cli/bundle/output/unbundle.js
rename to local-cli/bundle/output/unbundle/as-indexed-file.js
index de265c7df..65243375a 100644
--- a/local-cli/bundle/output/unbundle.js
+++ b/local-cli/bundle/output/unbundle/as-indexed-file.js
@@ -10,16 +10,19 @@
 
 const fs = require('fs');
 const Promise = require('promise');
-const writeFile = require('./writeFile');
+const writeSourceMap = require('./write-sourcemap');
 
 const MAGIC_UNBUNDLE_FILE_HEADER = 0xFB0BD1E5;
 const MAGIC_STARTUP_MODULE_ID = '';
 
-function buildBundle(packagerClient, requestOptions) {
-  return packagerClient.buildBundle({...requestOptions, unbundle: true});
-}
-
-function saveUnbundle(bundle, options, log) {
+/**
+ * Saves all JS modules of an app as a single file, separated with null bytes.
+ * The file begins with an offset table that contains module ids and their
+ * lengths/offsets.
+ * The module id for the startup code (prelude, polyfills etc.) is the
+ * empty string.
+ */
+function saveAsIndexedFile(bundle, options, log) {
   const {
     'bundle-output': bundleOutput,
     'bundle-encoding': encoding,
@@ -39,21 +42,24 @@ function saveUnbundle(bundle, options, log) {
 
   writeUnbundle.then(() => log('Done writing unbundle output'));
 
-  if (sourcemapOutput) {
-    log('Writing sourcemap output to:', sourcemapOutput);
-    const writeMap = writeFile(sourcemapOutput, '', null);
-    writeMap.then(() => log('Done writing sourcemap output'));
-    return Promise.all([writeUnbundle, writeMap]);
-  } else {
-    return writeUnbundle;
-  }
+  return Promise.all([writeUnbundle, writeSourceMap(sourcemapOutput, '', log)]);
 }
 
 /* global Buffer: true */
+
 const fileHeader = Buffer(4);
 fileHeader.writeUInt32LE(MAGIC_UNBUNDLE_FILE_HEADER);
 const nullByteBuffer = Buffer(1).fill(0);
 
+function writeBuffers(stream, buffers) {
+  buffers.forEach(buffer => stream.write(buffer));
+  return new Promise((resolve, reject) => {
+    stream.on('error', reject);
+    stream.on('finish', () => resolve());
+    stream.end();
+  });
+}
+
 const moduleToBuffer = ({name, code}, encoding) => ({
   name,
   buffer: Buffer.concat([
@@ -62,16 +68,9 @@ const moduleToBuffer = ({name, code}, encoding) => ({
   ])
 });
 
-function buildModuleBuffers(startupCode, modules, encoding) {
-  return (
-    [moduleToBuffer({name: '', code: startupCode}, encoding)]
-      .concat(modules.map(module => moduleToBuffer(module, encoding)))
-  );
-}
-
 function uInt32Buffer(n) {
   const buffer = Buffer(4);
-  buffer.writeUInt32LE(n, 0); // let's assume LE for now :)
+  buffer.writeUInt32LE(n, 0);
   return buffer;
 }
 
@@ -109,21 +108,17 @@ function buildModuleTable(buffers) {
   return Buffer.concat(offsetTable);
 }
 
+function buildModuleBuffers(startupCode, modules, encoding) {
+  return (
+    [moduleToBuffer({name: '', code: startupCode}, encoding)]
+      .concat(modules.map(module => moduleToBuffer(module, encoding)))
+  );
+}
+
 function buildTableAndContents(startupCode, modules, encoding) {
   const buffers = buildModuleBuffers(startupCode, modules, encoding);
   const table = buildModuleTable(buffers, encoding);
   return [fileHeader, table].concat(buffers.map(({buffer}) => buffer));
 }
 
-function writeBuffers(stream, buffers) {
-  buffers.forEach(buffer => stream.write(buffer));
-  return new Promise((resolve, reject) => {
-    stream.on('error', reject);
-    stream.on('finish', () => resolve());
-    stream.end();
-  });
-}
-
-exports.build = buildBundle;
-exports.save = saveUnbundle;
-exports.formatName = 'bundle';
+module.exports = saveAsIndexedFile;
diff --git a/local-cli/bundle/output/unbundle/index.js b/local-cli/bundle/output/unbundle/index.js
new file mode 100644
index 000000000..eb34cbbbf
--- /dev/null
+++ b/local-cli/bundle/output/unbundle/index.js
@@ -0,0 +1,29 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+'use strict';
+
+const asIndexedFile = require('./as-indexed-file');
+const asAssets = require('./as-assets');
+
+function buildBundle(packagerClient, requestOptions) {
+  return packagerClient.buildBundle({...requestOptions, unbundle: true});
+}
+
+function saveUnbundle(bundle, options, log) {
+  // we fork here depending on the platform:
+  // while android is pretty good at loading individual assets, ios has a large
+  // overhead when reading hundreds pf assets from disk
+  return options.platform === 'android' ?
+    asAssets(bundle, options, log) :
+    asIndexedFile(bundle, options, log);
+}
+
+exports.build = buildBundle;
+exports.save = saveUnbundle;
+exports.formatName = 'bundle';
diff --git a/local-cli/bundle/output/unbundle/write-sourcemap.js b/local-cli/bundle/output/unbundle/write-sourcemap.js
new file mode 100644
index 000000000..b194b9922
--- /dev/null
+++ b/local-cli/bundle/output/unbundle/write-sourcemap.js
@@ -0,0 +1,24 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+'use strict';
+
+const Promise = require('promise');
+const writeFile = require('../writeFile');
+
+function writeSourcemap(fileName, contents, log) {
+  if (!fileName) {
+    return Promise.resolve();
+  }
+  log('Writing sourcemap output to:', fileName);
+  const writeMap = writeFile(fileName, '', null);
+  writeMap.then(() => log('Done writing sourcemap output'));
+  return writeMap;
+}
+
+module.exports = writeSourcemap;