diff --git a/core/Makefile b/core/Makefile
index 46b23f8..083d3c9 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -111,7 +111,14 @@
 
 # The string used to uniquely identify this build;  used by the OTA server.
 ifeq (,$(strip $(BUILD_FINGERPRINT)))
-  BUILD_FINGERPRINT := $(PRODUCT_BRAND)/$(TARGET_PRODUCT)/$(TARGET_DEVICE):$(PLATFORM_VERSION)/$(BUILD_ID)/$(BUILD_NUMBER):$(TARGET_BUILD_VARIANT)/$(BUILD_VERSION_TAGS)
+  ifneq ($(filter eng.%,$(BUILD_NUMBER)),)
+    # Trim down BUILD_FINGERPRINT: the default BUILD_NUMBER makes it easily exceed
+    # the Android system property length limit (PROPERTY_VALUE_MAX=92).
+    BF_BUILD_NUMBER := $(USER)$(shell date +%m%d%H%M)
+  else
+    BF_BUILD_NUMBER := $(BUILD_NUMBER)
+  endif
+  BUILD_FINGERPRINT := $(PRODUCT_BRAND)/$(TARGET_PRODUCT)/$(TARGET_DEVICE):$(PLATFORM_VERSION)/$(BUILD_ID)/$(BF_BUILD_NUMBER):$(TARGET_BUILD_VARIANT)/$(BUILD_VERSION_TAGS)
 endif
 ifneq ($(words $(BUILD_FINGERPRINT)),1)
   $(error BUILD_FINGERPRINT cannot contain spaces: "$(BUILD_FINGERPRINT)")
diff --git a/core/build_id.mk b/core/build_id.mk
index aaf4185..f94b224 100644
--- a/core/build_id.mk
+++ b/core/build_id.mk
@@ -18,6 +18,6 @@
 # (like "CRB01").  It must be a single word, and is
 # capitalized by convention.
 
-BUILD_ID := OPENMASTER
+BUILD_ID := AOSP
 
 DISPLAY_BUILD_NUMBER := true