diff --git a/core/dex_preopt.mk b/core/dex_preopt.mk
index 0b85dc6..4918a2b 100644
--- a/core/dex_preopt.mk
+++ b/core/dex_preopt.mk
@@ -71,5 +71,4 @@
 else
 $(warning No DALVIK_VM_LIB, disable dexpreopt.)
 WITH_DEXPREOPT := false
-DISABLE_DEXPREOPT := true
 endif  # DALVIK_VM_LIB is defined.
diff --git a/core/main.mk b/core/main.mk
index 50703c2..a0310a7 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -348,7 +348,7 @@
   # Turn on Dalvik preoptimization for user builds, but only if not
   # explicitly disabled and the build is running on Linux (since host
   # Dalvik isn't built for non-Linux hosts).
-  ifneq (true,$(DISABLE_DEXPREOPT))
+  ifeq (,$(WITH_DEXPREOPT))
     ifeq ($(user_variant),user)
       ifeq ($(HOST_OS),linux)
         WITH_DEXPREOPT := true
diff --git a/target/board/generic_x86/BoardConfig.mk b/target/board/generic_x86/BoardConfig.mk
index db89582..c634bcd 100644
--- a/target/board/generic_x86/BoardConfig.mk
+++ b/target/board/generic_x86/BoardConfig.mk
@@ -24,7 +24,7 @@
 # Enable dex-preoptimization to speed up the first boot sequence
 # of an SDK AVD. Note that this operation only works on Linux for now
 ifeq ($(HOST_OS),linux)
-WITH_DEXPREOPT := true
+WITH_DEXPREOPT ?= true
 endif
 
 # Build OpenGLES emulation host and guest libraries
diff --git a/target/board/generic_x86_64/BoardConfig.mk b/target/board/generic_x86_64/BoardConfig.mk
index b58336a..7f2715e 100755
--- a/target/board/generic_x86_64/BoardConfig.mk
+++ b/target/board/generic_x86_64/BoardConfig.mk
@@ -30,7 +30,7 @@
 # Enable dex-preoptimization to speed up the first boot sequence
 # of an SDK AVD. Note that this operation only works on Linux for now
 ifeq ($(HOST_OS),linux)
-WITH_DEXPREOPT := true
+WITH_DEXPREOPT ?= true
 endif
 
 # disable the emulator
diff --git a/target/board/vbox_x86/BoardConfig.mk b/target/board/vbox_x86/BoardConfig.mk
index 815ad9e..e5a1d3e 100644
--- a/target/board/vbox_x86/BoardConfig.mk
+++ b/target/board/vbox_x86/BoardConfig.mk
@@ -3,7 +3,6 @@
 #
 
 TARGET_ARCH=x86
-DISABLE_DEXPREOPT := true
 TARGET_COMPRESS_MODULE_SYMBOLS := false
 TARGET_NO_RECOVERY := true
 TARGET_HARDWARE_3D := false
@@ -32,6 +31,7 @@
 # Reserve 265M  for the system partition
 BOARD_SYSTEMIMAGE_PARTITION_SIZE := 268435456
 
+WITH_DEXPREOPT := false
 
 # The eth0 device should be started with dhcp on boot.
 # Useful for emulators that don't provide a wifi connection.