diff --git a/core/config.mk b/core/config.mk
index 3e527a8..51810aa 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -675,8 +675,12 @@
 # Set up RS prebuilt variables for compatibility library
 
 RS_PREBUILT_CLCORE := prebuilts/sdk/renderscript/lib/$(TARGET_ARCH)/librsrt_$(TARGET_ARCH).bc
-RS_PREBUILT_LIBPATH := -L prebuilts/ndk/8/platforms/android-9/arch-$(TARGET_ARCH)/usr/lib
 RS_PREBUILT_COMPILER_RT := prebuilts/sdk/renderscript/lib/$(TARGET_ARCH)/libcompiler_rt.a
+ifeq (true,$(TARGET_IS_64_BIT))
+RS_PREBUILT_LIBPATH := -L prebuilts/ndk/9/platforms/android-21/arch-$(TARGET_ARCH)/usr/lib
+else
+RS_PREBUILT_LIBPATH := -L prebuilts/ndk/8/platforms/android-9/arch-$(TARGET_ARCH)/usr/lib
+endif
 
 # API Level lists for Renderscript Compat lib.
 RSCOMPAT_32BIT_ONLY_API_LEVELS := 8 9 10 11 12 13 14 15 16 17 18 19 20
diff --git a/core/java.mk b/core/java.mk
index 0ff59fc..bac5ca7 100644
--- a/core/java.mk
+++ b/core/java.mk
@@ -148,19 +148,29 @@
 RenderScript_file_stamp := $(LOCAL_INTERMEDIATE_SOURCE_DIR)/RenderScript.stamp
 renderscript_intermediate.COMMON := $(LOCAL_INTERMEDIATE_SOURCE_DIR)/renderscript
 
+# Defaulting to an empty string uses the latest available platform SDK.
 renderscript_target_api :=
 
 ifneq (,$(LOCAL_RENDERSCRIPT_TARGET_API))
-renderscript_target_api := $(LOCAL_RENDERSCRIPT_TARGET_API)
+  renderscript_target_api := $(LOCAL_RENDERSCRIPT_TARGET_API)
 else
-ifneq (,$(LOCAL_SDK_VERSION))
-# Set target-api for LOCAL_SDK_VERSIONs other than current.
-ifneq (,$(filter-out current system_current, $(LOCAL_SDK_VERSION)))
-renderscript_target_api := $(LOCAL_SDK_VERSION)
-endif
-endif  # LOCAL_SDK_VERSION is set
+  ifneq (,$(LOCAL_SDK_VERSION))
+    # Set target-api for LOCAL_SDK_VERSIONs other than current.
+    ifneq (,$(filter-out current system_current, $(LOCAL_SDK_VERSION)))
+      renderscript_target_api := $(LOCAL_SDK_VERSION)
+    endif
+  endif  # LOCAL_SDK_VERSION is set
 endif  # LOCAL_RENDERSCRIPT_TARGET_API is set
 
+# For 64-bit, we always have to upgrade to at least 21 for compat build.
+ifneq ($(LOCAL_RENDERSCRIPT_COMPATIBILITY),)
+  ifeq ($(TARGET_IS_64_BIT),true)
+    ifneq ($(filter $(RSCOMPAT_32BIT_ONLY_API_LEVELS),$(renderscript_target_api)),)
+      renderscript_target_api := 21
+    endif
+  endif
+endif
+
 ifeq ($(LOCAL_RENDERSCRIPT_CC),)
 LOCAL_RENDERSCRIPT_CC := $(LLVM_RS_CC)
 endif
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index e384526..c481bbc 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -80,7 +80,7 @@
     # assuming the device can only support APIs as of the previous official
     # public release.
     # This value will always be 0 for release builds.
-    PLATFORM_PREVIEW_SDK_VERSION := 2
+    PLATFORM_PREVIEW_SDK_VERSION := 3
   endif
 endif
 
diff --git a/tools/releasetools/ota_from_target_files.py b/tools/releasetools/ota_from_target_files.py
index 82d6313..531a728 100755
--- a/tools/releasetools/ota_from_target_files.py
+++ b/tools/releasetools/ota_from_target_files.py
@@ -832,9 +832,9 @@
   #    (allow recovery to mark itself finished and reboot)
 
   if OPTIONS.two_step:
-    if not OPTIONS.info_dict.get("multistage_support", None):
+    if not OPTIONS.source_info_dict.get("multistage_support", None):
       assert False, "two-step packages not supported by this build"
-    fs = OPTIONS.info_dict["fstab"]["/misc"]
+    fs = OPTIONS.source_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}
@@ -879,7 +879,8 @@
           GetBuildProp("ro.build.thumbprint", OPTIONS.source_info_dict))
 
   if updating_boot:
-    boot_type, boot_device = common.GetTypeAndDevice("/boot", OPTIONS.info_dict)
+    boot_type, boot_device = common.GetTypeAndDevice(
+        "/boot", OPTIONS.source_info_dict)
     d = common.Difference(target_boot, source_boot)
     _, _, d = d.ComputePatch()
     if d is None:
@@ -1218,9 +1219,9 @@
   #    (allow recovery to mark itself finished and reboot)
 
   if OPTIONS.two_step:
-    if not OPTIONS.info_dict.get("multistage_support", None):
+    if not OPTIONS.source_info_dict.get("multistage_support", None):
       assert False, "two-step packages not supported by this build"
-    fs = OPTIONS.info_dict["fstab"]["/misc"]
+    fs = OPTIONS.source_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}
@@ -1257,7 +1258,8 @@
 
     common.ZipWriteStr(output_zip, "patch/boot.img.p", d)
 
-    boot_type, boot_device = common.GetTypeAndDevice("/boot", OPTIONS.info_dict)
+    boot_type, boot_device = common.GetTypeAndDevice(
+        "/boot", OPTIONS.source_info_dict)
 
     script.PatchCheck("%s:%s:%d:%s:%d:%s" %
                       (boot_type, boot_device,