diff --git a/core/main.mk b/core/main.mk
index 81e2e31..8d6fddf 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -217,16 +217,22 @@
     # Disable debugging in plain user builds.
     enable_target_debugging :=
   endif
- 
-  # TODO: Always set WITH_DEXPREOPT (for user builds) once it works on OSX.
-  # Also, remove the corresponding block in config/product_config.make.
+
+  # TODO: Remove this and the corresponding block in
+  # config/product_config.make once host-based Dalvik preoptimization is
+  # working.
   ifeq ($(HOST_OS)-$(WITH_DEXPREOPT_buildbot),linux-true)
     WITH_DEXPREOPT := true
   endif
-  
+
+  # TODO: Always set WITH_HOST_DALVIK (for user builds) once it works on OSX.
+  ifeq ($(HOST_OS),linux)
+    WITH_HOST_DALVIK := true
+  endif
+
   # Disallow mock locations by default for user builds
   ADDITIONAL_DEFAULT_PROPERTIES += ro.allow.mock.location=0
-  
+
 else # !user_variant
   # Turn on checkjni for non-user builds.
   ADDITIONAL_BUILD_PROPERTIES += ro.kernel.android.checkjni=1
diff --git a/core/product_config.mk b/core/product_config.mk
index 50bc7bc..7f79ff7 100644
--- a/core/product_config.mk
+++ b/core/product_config.mk
@@ -119,12 +119,11 @@
     default_goal_substitution := $(DEFAULT_GOAL)
   endif
 
-  # Hack to make the linux build servers use dexpreopt.
-  # OSX is still a little flaky.  Most engineers don't use this
-  # type of target ("make PRODUCT-blah-user"), so this should
-  # only tend to happen when using buildbot.
-  # TODO: remove this and fix the matching lines in build/core/main.mk
-  # once dexpreopt works better on OSX.
+  # Hack to make the linux build servers use dexpreopt (emulator-based
+  # preoptimization). Most engineers don't use this type of target
+  # ("make PRODUCT-blah-user"), so this should only tend to happen when
+  # using buildbot.
+  # TODO: Remove this once host Dalvik preoptimization is working.
   ifeq ($(TARGET_BUILD_VARIANT),user)
     WITH_DEXPREOPT_buildbot := true
   endif