diff --git a/core/config.mk b/core/config.mk
index 998899e13..34f2c44e2 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -492,7 +492,16 @@ LLVM_RS_CC := $(HOST_OUT_EXECUTABLES)/llvm-rs-cc
 BCC_COMPAT := $(HOST_OUT_EXECUTABLES)/bcc_compat
 DEPMOD := $(HOST_OUT_EXECUTABLES)/depmod
 
+#TODO: use a smaller -Xmx value for most libraries;
+#      only core.jar and framework.jar need a heap this big.
+ifndef DX_ALT_JAR
 DX := $(HOST_OUT_EXECUTABLES)/dx
+DX_COMMAND := $(DX) -JXms16M -JXmx2048M
+else
+DX := $(DX_ALT_JAR)
+DX_COMMAND := java -Xms16M -Xmx2048M -jar $(DX)
+endif
+
 MAINDEXCLASSES := $(HOST_OUT_EXECUTABLES)/mainDexClasses
 
 SOONG_ZIP := $(SOONG_HOST_OUT_EXECUTABLES)/soong_zip
diff --git a/core/definitions.mk b/core/definitions.mk
index 593c14c33..5c39ecaee 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -2554,14 +2554,11 @@ $(hide) java -jar $(DESUGAR) \
 endef
 
 
-#TODO: use a smaller -Xmx value for most libraries;
-#      only core.jar and framework.jar need a heap this big.
 define transform-classes.jar-to-dex
 @echo "target Dex: $(PRIVATE_MODULE)"
 @mkdir -p $(dir $@)
 $(hide) rm -f $(dir $@)classes*.dex
-$(hide) $(DX) \
-    -JXms16M -JXmx2048M \
+$(hide) $(DX_COMMAND) \
     --dex --output=$(dir $@) \
     --min-sdk-version=$(call codename-or-sdk-to-sdk,$(PRIVATE_DEFAULT_APP_TARGET_SDK)) \
     $(if $(NO_OPTIMIZE_DX), \