diff --git a/core/config.mk b/core/config.mk
index 64743e0..911e0bf 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -846,7 +846,7 @@
 endif
 
 BUILD_NUMBER_FROM_FILE := $$(cat $(OUT_DIR)/build_number.txt)
-BUILD_DATETIME_FROM_FILE := $$(cat $(OUT_DIR)/build_date.txt)
+BUILD_DATETIME_FROM_FILE := $$(cat $(BUILD_DATETIME_FILE))
 
 # SEPolicy versions
 
diff --git a/core/main.mk b/core/main.mk
index 4d43295..0c165ca 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -60,8 +60,7 @@
 # without changing the command line every time.  Avoids rebuilds
 # when using ninja.
 $(shell mkdir -p $(OUT_DIR) && \
-    echo -n $(BUILD_NUMBER) > $(OUT_DIR)/build_number.txt && \
-    echo -n $(BUILD_DATETIME) > $(OUT_DIR)/build_date.txt)
+    echo -n $(BUILD_NUMBER) > $(OUT_DIR)/build_number.txt)
 ifeq ($(HOST_OS),darwin)
 DATE_FROM_FILE := date -r $(BUILD_DATETIME_FROM_FILE)
 else
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index d70dfb4..9f76bc8 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -24,7 +24,6 @@
 #     DEFAULT_APP_TARGET_SDK
 #     BUILD_ID
 #     BUILD_NUMBER
-#     BUILD_DATETIME
 #     PLATFORM_SECURITY_PATCH
 #     PLATFORM_VNDK_VERSION
 #     PLATFORM_SYSTEMSDK_VERSIONS
@@ -255,16 +254,10 @@
   BUILD_ID := UNKNOWN
 endif
 
-ifndef BUILD_DATETIME
-  # Used to reproduce builds by setting the same time. Must be the number
-  # of seconds since the Epoch.
-  BUILD_DATETIME := $(shell date +%s)
-endif
-
 ifneq (,$(findstring Darwin,$(UNAME)))
-DATE := date -r $(BUILD_DATETIME)
+DATE := date -r $(shell cat $(BUILD_DATETIME_FILE))
 else
-DATE := date -d @$(BUILD_DATETIME)
+DATE := date -d @$(shell cat $(BUILD_DATETIME_FILE))
 endif
 
 ifndef BUILD_NUMBER