diff --git a/CleanSpec.mk b/CleanSpec.mk
index c912497..c0525ad 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -208,6 +208,9 @@
 # 4.4.1
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/build.prop)
 
+# 4.4.2
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/build.prop)
+
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST
 # ************************************************
diff --git a/core/Makefile b/core/Makefile
index a8a7d97..8a1175e 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -1243,6 +1243,7 @@
 	@# build them.
 	$(hide) mkdir -p $(zip_root)/META
 	$(hide) $(ACP) $(APKCERTS_FILE) $(zip_root)/META/apkcerts.txt
+	$(hide) if test -e $(tool_extensions)/releasetools.py; then $(ACP) $(tool_extensions)/releasetools.py $(zip_root)/META/; fi
 	$(hide)	echo "$(PRODUCT_OTA_PUBLIC_KEYS)" > $(zip_root)/META/otakeys.txt
 	$(hide) echo "recovery_api_version=$(PRIVATE_RECOVERY_API_VERSION)" > $(zip_root)/META/misc_info.txt
 	$(hide) echo "fstab_version=$(PRIVATE_RECOVERY_FSTAB_VERSION)" >> $(zip_root)/META/misc_info.txt
@@ -1262,7 +1263,7 @@
 endif
 	$(hide) echo 'mkbootimg_args=$(BOARD_MKBOOTIMG_ARGS)' >> $(zip_root)/META/misc_info.txt
 	$(hide) echo "use_set_metadata=1" >> $(zip_root)/META/misc_info.txt
-	$(hide) echo "update_rename_support=1" >> $(zip_root)/META/misc_info.txt
+	$(hide) echo "multistage_support=1" >> $(zip_root)/META/misc_info.txt
 	$(call generate-userimage-prop-dictionary, $(zip_root)/META/misc_info.txt)
 	@# Zip everything up, preserving symlinks
 	$(hide) (cd $(zip_root) && zip -qry ../$(notdir $@) .)
diff --git a/core/droiddoc.mk b/core/droiddoc.mk
index 0d3094d..fd7f338 100644
--- a/core/droiddoc.mk
+++ b/core/droiddoc.mk
@@ -231,6 +231,8 @@
 	@mkdir -p $(dir $@)
 	$(hide) ( F=$$(pwd)/$@ ; cd $(PRIVATE_DOCS_DIR) && zip -rq $$F * )
 
+$(LOCAL_MODULE)-docs.zip : $(out_zip)
+
 $(call dist-for-goals,docs,$(out_zip))
 
 endif
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index 40248fc..99283b0 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -41,7 +41,7 @@
   # which is the version that we reveal to the end user.
   # Update this value when the platform version changes (rather
   # than overriding it somewhere else).  Can be an arbitrary string.
-  PLATFORM_VERSION := 4.4.3.2.1.000.000
+  PLATFORM_VERSION := 4.4.2
 endif
 
 ifeq "" "$(PLATFORM_SDK_VERSION)"
diff --git a/target/product/sdk.mk b/target/product/sdk.mk
index bc59782..4005e57 100644
--- a/target/product/sdk.mk
+++ b/target/product/sdk.mk
@@ -62,7 +62,8 @@
 	SmokeTest \
 	SmokeTestApp \
 	rild \
-	LegacyCamera
+	LegacyCamera \
+	Dialer
 
 # Define the host tools and libs that are parts of the SDK.
 -include sdk/build/product_sdk.mk
diff --git a/tools/droiddoc/templates-ds/jd_lists_unified.cs b/tools/droiddoc/templates-ds/jd_lists_unified.cs
new file mode 100644
index 0000000..417a5c1
--- /dev/null
+++ b/tools/droiddoc/templates-ds/jd_lists_unified.cs
@@ -0,0 +1 @@
+<?cs var:reference_tree ?>
diff --git a/tools/droiddoc/templates-pdk/jd_lists_unified.cs b/tools/droiddoc/templates-pdk/jd_lists_unified.cs
new file mode 100644
index 0000000..417a5c1
--- /dev/null
+++ b/tools/droiddoc/templates-pdk/jd_lists_unified.cs
@@ -0,0 +1 @@
+<?cs var:reference_tree ?>
diff --git a/tools/droiddoc/templates-sac/jd_lists_unified.cs b/tools/droiddoc/templates-sac/jd_lists_unified.cs
new file mode 100644
index 0000000..417a5c1
--- /dev/null
+++ b/tools/droiddoc/templates-sac/jd_lists_unified.cs
@@ -0,0 +1 @@
+<?cs var:reference_tree ?>
diff --git a/tools/droiddoc/templates-sdk/assets/css/default.css b/tools/droiddoc/templates-sdk/assets/css/default.css
index c4b81d2..c3eb8bc 100644
--- a/tools/droiddoc/templates-sdk/assets/css/default.css
+++ b/tools/droiddoc/templates-sdk/assets/css/default.css
@@ -1897,6 +1897,10 @@
   font-size:inherit;
 }
 
+.sidebox > *:last-child {
+  margin-bottom:0;
+}
+
 #tb ol,
 #tb ul,
 #qv ul {
@@ -2259,12 +2263,16 @@
 
 
 /* nav tree */
-#side-nav, #devdoc-nav, #swapper,
+#side-nav, #swapper,
 #nav-tree, #tree-list {
   overflow:hidden;
   margin-left:0;
 }
 
+#devdoc-nav {
+  overflow:visible !important; /* To keep the "to top" button visible */
+}
+
 #nav-tree ul {
   list-style:none;
   padding:0;
@@ -2497,7 +2505,7 @@
 }
 
 /* --------------------------------------------------------------------------
-Styles for samples project trees and code browsing in resources tab 
+Styles for samples browser
 */
 
 #codesample-wrapper {
@@ -2543,6 +2551,30 @@
   display:inline-block;
 }
 
+/*
+Styles for displaying image or video resources in samples browser.
+Resources are marked as no-display if they exceed the size limit.
+*/
+div#codesample-resource img, div#codesample-resource video {
+  border: 1px solid #ececec;
+}
+
+div#codesample-resource.noDisplay div {
+  border: 1px solid #ececec;
+  width:120px;
+  margin-bottom:4px;
+  padding:20px;
+}
+
+div#codesample-resource .noDisplay-message:after {
+  font-style:italic;
+  font-size:12px;
+  content: 'This resource is not available for browsing. To view it, please download the project.';
+}
+
+/*
+Styles for project structure (treeview) page
+*/
 .structure-dir {
 background-image:url(../../assets/images/folder.png);
 background-repeat:no-repeat;
@@ -4791,25 +4823,32 @@
 
 .landing-banner,
 .landing-docs {
-  margin:20px 0 0;
+  margin:20px 0;
 }
-.landing-banner div:first-child,
-.landing-docs div:first-child,
-.landing-docs .col-12 {
+.landing-banner > div:first-child,
+.landing-docs > div:first-child,
+.landing-docs > .col-12 {
   margin-left:0;
   min-height:280px;
 }
-.landing-banner div:last-child,
-.landing-docs div:last-child,
-.landing-docs .col-12 {
+.landing-banner.short > div {
+  min-height:50px;
+}
+.landing-banner > div:last-child,
+.landing-docs > div:last-child,
+.landing-docs > .col-12 {
   margin-right:0;
 }
 
+.landing-banner > div > *:last-child {
+  margin-bottom:0;
+}
 .landing-banner h1 {
   margin-top:0;
 }
-.landing-docs {
-  clear:left;
+.landing-docs,
+.landing-banner {
+  clear:both;
   overflow:hidden;
 }
 .landing-docs h3 {
@@ -4839,6 +4878,32 @@
 
 
 
+.next-docs {
+  border-top:1px solid #ccc;
+  margin:40px 0 0;
+  padding:5px 0 0;
+  clear:left;
+  overflow:hidden;
+}
+.next-docs div:first-child {
+  margin-left:0;
+}
+.next-docs div:last-child {
+  margin-right:0;
+}
+
+.next-docs h2 {
+  font-size:14px;
+  line-height:21px;
+  color:#555;
+  text-transform:uppercase;
+  border-bottom:none;
+  margin:0;
+  padding:5px 0 0;
+}
+
+
+
 /************* HOME/LANDING PAGE *****************/
 
 .slideshow-home {
diff --git a/tools/droiddoc/templates-sdk/customizations.cs b/tools/droiddoc/templates-sdk/customizations.cs
index d54d371..ed57f1c 100644
--- a/tools/droiddoc/templates-sdk/customizations.cs
+++ b/tools/droiddoc/templates-sdk/customizations.cs
@@ -144,12 +144,8 @@
 <?cs
         include:"../../../../frameworks/base/docs/html/samples/samples_toc.cs" ?>
 
-
       </div>
-      <script type="text/javascript">
-       showSamplesRefTree();
 
-      </script>
     </div> <!-- end side-nav -->
     <script>
       $(document).ready(function() {
diff --git a/tools/droiddoc/templates-sdk/docpage.cs b/tools/droiddoc/templates-sdk/docpage.cs
index 6faac04..74c7cd2 100644
--- a/tools/droiddoc/templates-sdk/docpage.cs
+++ b/tools/droiddoc/templates-sdk/docpage.cs
@@ -74,11 +74,20 @@
     <?cs /if ?><?cs # end if training ?>
   </div>
   <?cs /if ?>
+<?cs elif:samplesProjectIndex ?>
+  <div id="api-info-block">
+  <div class="sum-details-links">
+  Overview
+  &#124; <a href="<?cs var:toroot ?>samples/<?cs var:projectDir ?>/project.html">Project</a>
+  &#124; <a href="<?cs var:toroot ?>downloads/samples/<?cs var:projectDir ?>.zip">Download</a>
+  </div><!-- end sum-details-links -->
+  </div><!-- end breadcurmb block -->
+  <h1 itemprop="name"><?cs var:projectDir ?></h1>
 <?cs else ?>
   <?cs if:(!fullpage && !header.hide) ?>
     <?cs if:page.landing ?><?cs # header logic for docs that are landing pages ?>
       <div class="landing-banner">
-        <?cs if:page.landing.image ?><?cs # use two-column layout only if there's an image ?>
+        <?cs if:page.landing.image ?><?cs # use two-column layout only if there is an image ?>
         <div class="col-6">
           <img src="<?cs var:toroot ?><?cs var:page.landing.image ?>" alt="" />
         </div>
diff --git a/tools/droiddoc/templates-sdk/head_tag.cs b/tools/droiddoc/templates-sdk/head_tag.cs
index 379829c..54de169 100644
--- a/tools/droiddoc/templates-sdk/head_tag.cs
+++ b/tools/droiddoc/templates-sdk/head_tag.cs
@@ -50,6 +50,7 @@
 /if ?>
 <script type="text/javascript">
   var toRoot = "<?cs var:toroot ?>";
+  var metaTags = [<?cs var:meta.tags ?>];
   var devsite = <?cs if:devsite ?>true<?cs else ?>false<?cs /if ?>;
 </script>
 <script src="<?cs var:toroot ?>assets/js/docs.js" type="text/javascript"></script>
diff --git a/tools/droiddoc/templates-sdk/jd_lists_unified.cs b/tools/droiddoc/templates-sdk/jd_lists_unified.cs
new file mode 100644
index 0000000..417a5c1
--- /dev/null
+++ b/tools/droiddoc/templates-sdk/jd_lists_unified.cs
@@ -0,0 +1 @@
+<?cs var:reference_tree ?>
diff --git a/tools/droiddoc/templates-sdk/sample.cs b/tools/droiddoc/templates-sdk/sample.cs
index 3fed799..04c8d4b 100644
--- a/tools/droiddoc/templates-sdk/sample.cs
+++ b/tools/droiddoc/templates-sdk/sample.cs
@@ -27,7 +27,7 @@
 
 <div id="pathCrumb">
 <?cs each:item = parentdirs ?>
-  <?cs if:pathCrumbLinks
+  <?cs if:LinkifyPathCrumb
     ?><a href="<?cs var:toroot ?><?cs var:item.Link ?>"><?cs var:item.Name ?></a> / 
   <?cs else
     ?><?cs var:item.Name ?> / <?cs /if ?>
@@ -50,18 +50,37 @@
 <?cs var:summary ?>
 
 <!-- begin file contents -->
-<div id="codesample-wrapper">
-<pre id="codesample-line-numbers" class="no-pretty-print hidden"></pre>
-<pre id="codesample-block"><?cs var:fileContents ?></pre>
-</div>
+
+<?cs # embed image/videos if below maxsize (show message otherwise), else display source code ?>
+<?cs if:resType == "img" ?>
+  <div id="codesample-resource"
+    <?cs if:noDisplay ?>
+      class="noDisplay"><div class="noDisplay-message"></div>
+    <?cs else ?>
+      ><img src="<?cs var:realFile ?>" title="<?cs var:page.title ?>">
+    <?cs /if ?>
+  </div>
+<?cs elif:resType == "video" ?>
+  <div id="codesample-resource"
+    <?cs if:noDisplay ?>
+      class="noDisplay"><div class="noDisplay-message"></div>
+    <?cs else ?>
+      ><video class="play-on-hover" controls style="border:1px solid #ececec;background-color:#f9f9f9;" poster="">
+        <source src="<?cs var:page.title ?>">
+      </video>
+    <?cs /if ?>
+  </div>
+<?cs else ?>
+  <div id="codesample-wrapper">
+    <pre id="codesample-line-numbers" class="no-pretty-print hidden"></pre>
+    <pre id="codesample-block"><?cs var:fileContents ?></pre>
+  </div>
+  <script type="text/javascript">
+  initCodeLineNumbers();
+  </script>
+<?cs /if ?>
 
 <!-- end file contents -->
-<script type="text/javascript">
-  initCodeLineNumbers();
-</script>
-
-
-
 
 <?cs else ?><?cs
   # else, this means it's offline docs,
@@ -69,6 +88,49 @@
 
 <?cs /if ?><?cs # end if/else online docs ?>
 
+      <div class="content-footer <?cs
+                    if:fullpage ?>wrap<?cs
+                    else ?>layout-content-row<?cs /if ?>"
+                    itemscope itemtype="http://schema.org/SiteNavigationElement">
+        <div class="layout-content-col <?cs
+                    if:fullpage ?>col-16<?cs
+                    elif:training||guide ?>col-8<?cs
+                    else ?>col-9<?cs /if ?>" style="padding-top:4px">
+          <?cs if:!page.noplus ?><?cs if:fullpage ?><style>#___plusone_0 {float:right !important;}</style><?cs /if ?>
+            <div class="g-plusone" data-size="medium"></div>
+          <?cs /if ?>
+        </div>
+        <?cs if:!fullscreen ?>
+        <div class="paging-links layout-content-col col-4">
+          <?cs if:(design||training||walkthru) && !page.landing && !page.trainingcourse && !footer.hide ?>
+            <a href="#" class="prev-page-link hide"
+                zh-tw-lang="上一堂課"
+                zh-cn-lang="上一课"
+                ru-lang="Предыдущий"
+                ko-lang="이전"
+                ja-lang="前へ"
+                es-lang="Anterior"
+                >Previous</a>
+            <a href="#" class="next-page-link hide"
+                zh-tw-lang="下一堂課"
+                zh-cn-lang="下一课"
+                ru-lang="Следующий"
+                ko-lang="다음"
+                ja-lang="次へ"
+                es-lang="Siguiente"
+                >Next</a>
+          <?cs /if ?>
+        </div>
+        <?cs /if ?>
+      </div>
+
+      <?cs # for training classes, provide a different kind of link when the next page is a different class ?>
+      <?cs if:training && !page.article ?>
+      <div class="layout-content-row content-footer next-class" style="display:none" itemscope itemtype="http://schema.org/SiteNavigationElement">
+          <a href="#" class="next-class-link hide">Next class: </a>
+      </div>
+      <?cs /if ?>
+
   </div> <!-- end jd-content -->
 
 <?cs include:"footer.cs" ?>
diff --git a/tools/droiddoc/templates-sdk/sampleindex.cs b/tools/droiddoc/templates-sdk/sampleindex.cs
index 8db15c4..98767b1 100644
--- a/tools/droiddoc/templates-sdk/sampleindex.cs
+++ b/tools/droiddoc/templates-sdk/sampleindex.cs
@@ -20,7 +20,9 @@
 &#124; Project<?cs else ?>Overview
 &#124; <a href="<?cs var:toroot ?>samples/<?cs var:projectDir ?>/project.html">Project</a>
 <?cs /if ?>
-&#124; <a href="<?cs var:toroot ?>downloads/samples/<?cs var:projectDir ?>.zip">Download</a>
+&#124; <a href="<?cs var:toroot ?>downloads/samples/<?cs var:projectDir ?>.zip"
+    onclick="_gaq.push(['_trackEvent', 'Samples', 'Download', <?cs var:projectDir ?>]);"
+    >Download</a>
 
 </div><!-- end sum-details-links -->
 
@@ -78,6 +80,48 @@
           so don't show src links (we dont have the pages!) ?>
 
 <?cs /if ?><?cs # end if/else online docs ?>
+      <div class="content-footer <?cs
+                    if:fullpage ?>wrap<?cs
+                    else ?>layout-content-row<?cs /if ?>"
+                    itemscope itemtype="http://schema.org/SiteNavigationElement">
+        <div class="layout-content-col <?cs
+                    if:fullpage ?>col-16<?cs
+                    elif:training||guide ?>col-8<?cs
+                    else ?>col-9<?cs /if ?>" style="padding-top:4px">
+          <?cs if:!page.noplus ?><?cs if:fullpage ?><style>#___plusone_0 {float:right !important;}</style><?cs /if ?>
+            <div class="g-plusone" data-size="medium"></div>
+          <?cs /if ?>
+        </div>
+        <?cs if:!fullscreen ?>
+        <div class="paging-links layout-content-col col-4">
+          <?cs if:(design||training||walkthru) && !page.landing && !page.trainingcourse && !footer.hide ?>
+            <a href="#" class="prev-page-link hide"
+                zh-tw-lang="上一堂課"
+                zh-cn-lang="上一课"
+                ru-lang="Предыдущий"
+                ko-lang="이전"
+                ja-lang="前へ"
+                es-lang="Anterior"
+                >Previous</a>
+            <a href="#" class="next-page-link hide"
+                zh-tw-lang="下一堂課"
+                zh-cn-lang="下一课"
+                ru-lang="Следующий"
+                ko-lang="다음"
+                ja-lang="次へ"
+                es-lang="Siguiente"
+                >Next</a>
+          <?cs /if ?>
+        </div>
+        <?cs /if ?>
+      </div>
+
+      <?cs # for training classes, provide a different kind of link when the next page is a different class ?>
+      <?cs if:training && !page.article ?>
+      <div class="layout-content-row content-footer next-class" style="display:none" itemscope itemtype="http://schema.org/SiteNavigationElement">
+          <a href="#" class="next-class-link hide">Next class: </a>
+      </div>
+      <?cs /if ?>
 
   </div> <!-- end jd-content -->
 
diff --git a/tools/droiddoc/templates-sdk/sdkpage.cs b/tools/droiddoc/templates-sdk/sdkpage.cs
index ecc26f5..38af569 100644
--- a/tools/droiddoc/templates-sdk/sdkpage.cs
+++ b/tools/droiddoc/templates-sdk/sdkpage.cs
@@ -491,6 +491,7 @@
       $("#sdk-terms-form,.sdk-terms-intro").fadeOut('slow');
       $("#next-steps").fadeIn('slow');
       $("h1#tos-header").text('Get Ready to Code!');
+      _gaq.push(['_trackEvent', 'SDK', 'ADT and Tools', $("#downloadForRealz").html()]);
       return true;
     } else {
       $("label#agreeLabel,#bitpicker input").parent().stop().animate({color: "#258AAF"}, 200,
diff --git a/tools/releasetools/edify_generator.py b/tools/releasetools/edify_generator.py
index 189672c..2c3b9e7 100644
--- a/tools/releasetools/edify_generator.py
+++ b/tools/releasetools/edify_generator.py
@@ -184,11 +184,6 @@
     cmd = "delete(" + ",\0".join(['"%s"' % (i,) for i in file_list]) + ");"
     self.script.append(self._WordWrap(cmd))
 
-  def RenameFile(self, srcfile, tgtfile):
-    """Moves a file from one location to another."""
-    if self.info.get("update_rename_support", False):
-      self.script.append('rename("%s", "%s");' % (srcfile, tgtfile))
-
   def ApplyPatch(self, srcfile, tgtfile, tgtsize, tgtsha1, *patchpairs):
     """Apply binary patches (in *patchpairs) to the given srcfile to
     produce tgtfile (which may be "-" to indicate overwriting the
diff --git a/tools/releasetools/ota_from_target_files b/tools/releasetools/ota_from_target_files
index 2ef896f..28e8513 100755
--- a/tools/releasetools/ota_from_target_files
+++ b/tools/releasetools/ota_from_target_files
@@ -52,6 +52,11 @@
   -a  (--aslr_mode)  <on|off>
       Specify whether to turn on ASLR for the package (on by default).
 
+  -2  (--two_step)
+      Generate a 'two-step' OTA package, where recovery is updated
+      first, so that any changes made to the system partition are done
+      using the new recovery (new kernel, etc.).
+
 """
 
 import sys
@@ -88,6 +93,7 @@
 OPTIONS.extra_script = None
 OPTIONS.aslr_mode = True
 OPTIONS.worker_threads = 3
+OPTIONS.two_step = False
 
 def MostPopularKey(d, default):
   """Given a dict, return the key corresponding to the largest
@@ -108,31 +114,6 @@
   symlink."""
   return (info.external_attr >> 28) == 010
 
-def ClosestFileMatch(src, tgtfiles, existing):
-  """Returns the closest file match between a source file and list
-     of potential matches.  The exact filename match is preferred,
-     then the sha1 is searched for, and finally a file with the same
-     basename is evaluated.  Rename support in the updater-binary is
-     required for the latter checks to be used."""
-
-  result = tgtfiles.get("path:" + src.name)
-  if result is not None:
-    return result
-
-  if not OPTIONS.target_info_dict.get("update_rename_support", False):
-    return None
-
-  if src.size < 1000:
-    return None
-
-  result = tgtfiles.get("sha1:" + src.sha1)
-  if result is not None and existing.get(result.name) is None:
-    return result
-  result = tgtfiles.get("file:" + src.name.split("/")[-1])
-  if result is not None and existing.get(result.name) is None:
-    return result
-  return None
-
 class Item:
   """Items represent the metadata (user, group, mode) of files and
   directories in the system image."""
@@ -429,6 +410,46 @@
 
   AppendAssertions(script, OPTIONS.info_dict)
   device_specific.FullOTA_Assertions()
+
+  # Two-step package strategy (in chronological order, which is *not*
+  # the order in which the generated script has things):
+  #
+  # if stage is not "2/3" or "3/3":
+  #    write recovery image to boot partition
+  #    set stage to "2/3"
+  #    reboot to boot partition and restart recovery
+  # else if stage is "2/3":
+  #    write recovery image to recovery partition
+  #    set stage to "3/3"
+  #    reboot to recovery partition and restart recovery
+  # else:
+  #    (stage must be "3/3")
+  #    set stage to ""
+  #    do normal full package installation:
+  #       wipe and install system, boot image, etc.
+  #       set up system to update recovery partition on first boot
+  #    complete script normally (allow recovery to mark itself finished and reboot)
+
+  recovery_img = common.GetBootableImage("recovery.img", "recovery.img",
+                                         OPTIONS.input_tmp, "RECOVERY")
+  if OPTIONS.two_step:
+    if not OPTIONS.info_dict.get("multistage_support", None):
+      assert False, "two-step packages not supported by this build"
+    fs = OPTIONS.info_dict["fstab"]["/misc"]
+    assert fs.fs_type.upper() == "EMMC", \
+        "two-step packages only supported on devices with EMMC /misc partitions"
+    bcb_dev = {"bcb_dev": fs.device}
+    common.ZipWriteStr(output_zip, "recovery.img", recovery_img.data)
+    script.AppendExtra("""
+if get_stage("%(bcb_dev)s", "stage") == "2/3" then
+""" % bcb_dev)
+    script.WriteRawImage("/recovery", "recovery.img")
+    script.AppendExtra("""
+set_stage("%(bcb_dev)s", "3/3");
+reboot_now("%(bcb_dev)s", "recovery");
+else if get_stage("%(bcb_dev)s", "stage") == "3/3" then
+""" % bcb_dev)
+
   device_specific.FullOTA_InstallBegin()
 
   script.ShowProgress(0.5, 0)
@@ -449,8 +470,6 @@
 
   boot_img = common.GetBootableImage("boot.img", "boot.img",
                                      OPTIONS.input_tmp, "BOOT")
-  recovery_img = common.GetBootableImage("recovery.img", "recovery.img",
-                                         OPTIONS.input_tmp, "RECOVERY")
   MakeRecoveryPatch(OPTIONS.input_tmp, output_zip, recovery_img, boot_img)
 
   Item.GetMetadata(input_zip)
@@ -470,6 +489,19 @@
     script.AppendExtra(OPTIONS.extra_script)
 
   script.UnmountAll()
+
+  if OPTIONS.two_step:
+    script.AppendExtra("""
+set_stage("%(bcb_dev)s", "");
+""" % bcb_dev)
+    script.AppendExtra("else\n")
+    script.WriteRawImage("/boot", "recovery.img")
+    script.AppendExtra("""
+set_stage("%(bcb_dev)s", "2/3");
+reboot_now("%(bcb_dev)s", "");
+endif;
+endif;
+""" % bcb_dev)
   script.AddToZip(input_zip, output_zip)
   WriteMetadata(metadata, output_zip)
 
@@ -539,27 +571,11 @@
   verbatim_targets = []
   patch_list = []
   diffs = []
-  renames = {}
   largest_source_size = 0
-
-  matching_file_cache = {}
-  for fn in source_data.keys():
-    sf = source_data[fn]
-    assert fn == sf.name
-    matching_file_cache["path:" + fn] = sf
-    # Only allow eligability for filename/sha matching
-    # if there isn't a perfect path match.
-    if target_data.get(sf.name) is None:
-      matching_file_cache["file:" + fn.split("/")[-1]] = sf
-      matching_file_cache["sha:" + sf.sha1] = sf
-
   for fn in sorted(target_data.keys()):
     tf = target_data[fn]
     assert fn == tf.name
-    sf = ClosestFileMatch(tf, matching_file_cache, renames)
-    if sf is not None and sf.name != tf.name:
-      print "File has moved from " + sf.name + " to " + tf.name
-      renames[sf.name] = tf
+    sf = source_data.get(fn, None)
 
     if sf is None or fn in OPTIONS.require_verbatim:
       # This file should be included verbatim
@@ -572,7 +588,7 @@
       # File is different; consider sending as a patch
       diffs.append(common.Difference(tf, sf))
     else:
-      # Target file data identical to source (may still be renamed)
+      # Target file identical to source.
       pass
 
   common.ComputeDifferences(diffs)
@@ -584,8 +600,8 @@
       tf.AddToZip(output_zip)
       verbatim_targets.append((tf.name, tf.size))
     else:
-      common.ZipWriteStr(output_zip, "patch/" + sf.name + ".p", d)
-      patch_list.append((sf.name, tf, sf, tf.size, common.sha1(d).hexdigest()))
+      common.ZipWriteStr(output_zip, "patch/" + tf.name + ".p", d)
+      patch_list.append((tf.name, tf, sf, tf.size, common.sha1(d).hexdigest()))
       largest_source_size = max(largest_source_size, sf.size)
 
   source_fp = GetBuildProp("ro.build.fingerprint", OPTIONS.source_info_dict)
@@ -601,7 +617,8 @@
       OPTIONS.source_info_dict)
   target_boot = common.GetBootableImage(
       "/tmp/boot.img", "boot.img", OPTIONS.target_tmp, "BOOT")
-  updating_boot = (source_boot.data != target_boot.data)
+  updating_boot = (not OPTIONS.two_step and
+                   (source_boot.data != target_boot.data))
 
   source_recovery = common.GetBootableImage(
       "/tmp/recovery.img", "recovery.img", OPTIONS.source_tmp, "RECOVERY",
@@ -619,6 +636,46 @@
   AppendAssertions(script, OPTIONS.target_info_dict)
   device_specific.IncrementalOTA_Assertions()
 
+  # Two-step incremental package strategy (in chronological order,
+  # which is *not* the order in which the generated script has
+  # things):
+  #
+  # if stage is not "2/3" or "3/3":
+  #    do verification on current system
+  #    write recovery image to boot partition
+  #    set stage to "2/3"
+  #    reboot to boot partition and restart recovery
+  # else if stage is "2/3":
+  #    write recovery image to recovery partition
+  #    set stage to "3/3"
+  #    reboot to recovery partition and restart recovery
+  # else:
+  #    (stage must be "3/3")
+  #    perform update:
+  #       patch system files, etc.
+  #       force full install of new boot image
+  #       set up system to update recovery partition on first boot
+  #    complete script normally (allow recovery to mark itself finished and reboot)
+
+  if OPTIONS.two_step:
+    if not OPTIONS.info_dict.get("multistage_support", None):
+      assert False, "two-step packages not supported by this build"
+    fs = OPTIONS.info_dict["fstab"]["/misc"]
+    assert fs.fs_type.upper() == "EMMC", \
+        "two-step packages only supported on devices with EMMC /misc partitions"
+    bcb_dev = {"bcb_dev": fs.device}
+    common.ZipWriteStr(output_zip, "recovery.img", target_recovery.data)
+    script.AppendExtra("""
+if get_stage("%(bcb_dev)s", "stage") == "2/3" then
+""" % bcb_dev)
+    script.AppendExtra("sleep(20);\n");
+    script.WriteRawImage("/recovery", "recovery.img")
+    script.AppendExtra("""
+set_stage("%(bcb_dev)s", "3/3");
+reboot_now("%(bcb_dev)s", "recovery");
+else if get_stage("%(bcb_dev)s", "stage") != "3/3" then
+""" % bcb_dev)
+
   script.Print("Verifying current system...")
 
   device_specific.IncrementalOTA_VerifyBegin()
@@ -656,10 +713,23 @@
 
   device_specific.IncrementalOTA_VerifyEnd()
 
+  if OPTIONS.two_step:
+    script.WriteRawImage("/boot", "recovery.img")
+    script.AppendExtra("""
+set_stage("%(bcb_dev)s", "2/3");
+reboot_now("%(bcb_dev)s", "");
+else
+""" % bcb_dev)
+
   script.Comment("---- start making changes here ----")
 
   device_specific.IncrementalOTA_InstallBegin()
 
+  if OPTIONS.two_step:
+    common.ZipWriteStr(output_zip, "boot.img", target_boot.data)
+    script.WriteRawImage("/boot", "boot.img")
+    print "writing full boot image (forced by two-step mode)"
+
   if OPTIONS.wipe_user_data:
     script.Print("Erasing user data...")
     script.FormatPartition("/data")
@@ -667,8 +737,7 @@
   script.Print("Removing unneeded files...")
   script.DeleteFiles(["/"+i[0] for i in verbatim_targets] +
                      ["/"+i for i in sorted(source_data)
-                            if i not in target_data and
-                            i not in renames] +
+                            if i not in target_data] +
                      ["/system/recovery.img"])
 
   script.ShowProgress(0.8, 0)
@@ -688,23 +757,24 @@
     so_far += tf.size
     script.SetProgress(so_far / total_patch_size)
 
-  if updating_boot:
-    # Produce the boot image by applying a patch to the current
-    # contents of the boot partition, and write it back to the
-    # partition.
-    script.Print("Patching boot image...")
-    script.ApplyPatch("%s:%s:%d:%s:%d:%s"
-                      % (boot_type, boot_device,
-                         source_boot.size, source_boot.sha1,
-                         target_boot.size, target_boot.sha1),
-                      "-",
-                      target_boot.size, target_boot.sha1,
-                      source_boot.sha1, "patch/boot.img.p")
-    so_far += target_boot.size
-    script.SetProgress(so_far / total_patch_size)
-    print "boot image changed; including."
-  else:
-    print "boot image unchanged; skipping."
+  if not OPTIONS.two_step:
+    if updating_boot:
+      # Produce the boot image by applying a patch to the current
+      # contents of the boot partition, and write it back to the
+      # partition.
+      script.Print("Patching boot image...")
+      script.ApplyPatch("%s:%s:%d:%s:%d:%s"
+                        % (boot_type, boot_device,
+                           source_boot.size, source_boot.sha1,
+                           target_boot.size, target_boot.sha1),
+                        "-",
+                        target_boot.size, target_boot.sha1,
+                        source_boot.sha1, "patch/boot.img.p")
+      so_far += target_boot.size
+      script.SetProgress(so_far / total_patch_size)
+      print "boot image changed; including."
+    else:
+      print "boot image unchanged; skipping."
 
   if updating_recovery:
     # Recovery is generated as a patch using both the boot image
@@ -755,13 +825,6 @@
     script.Print("Unpacking new recovery...")
     script.UnpackPackageDir("recovery", "/system")
 
-  if len(renames) > 0:
-    script.Print("Renaming files...")
-
-  for src in renames:
-    print "Renaming " + src + " to " + renames[src].name
-    script.RenameFile(src, renames[src].name)
-
   script.Print("Symlinks and permissions...")
 
   # Create all the symlinks that don't already exist, or point to
@@ -796,6 +859,13 @@
     script.ApplyPatch("/"+fn, "-", tf.size, tf.sha1, sf.sha1, "patch/"+fn+".p")
   script.SetPermissions("/system/build.prop", 0, 0, 0644, None, None)
 
+  if OPTIONS.two_step:
+    script.AppendExtra("""
+set_stage("%(bcb_dev)s", "");
+endif;
+endif;
+""" % bcb_dev)
+
   script.AddToZip(target_zip, output_zip)
   WriteMetadata(metadata, output_zip)
 
@@ -822,12 +892,14 @@
         OPTIONS.aslr_mode = False
     elif o in ("--worker_threads"):
       OPTIONS.worker_threads = int(a)
+    elif o in ("-2", "--two_step"):
+      OPTIONS.two_step = True
     else:
       return False
     return True
 
   args = common.ParseOptions(argv, __doc__,
-                             extra_opts="b:k:i:d:wne:a:",
+                             extra_opts="b:k:i:d:wne:a:2",
                              extra_long_opts=["board_config=",
                                               "package_key=",
                                               "incremental_from=",
@@ -836,6 +908,7 @@
                                               "extra_script=",
                                               "worker_threads=",
                                               "aslr_mode=",
+                                              "two_step",
                                               ],
                              extra_option_handler=option_handler)