diff --git a/core/version_util.mk b/core/version_util.mk
index 1f3fff6..259621e 100644
--- a/core/version_util.mk
+++ b/core/version_util.mk
@@ -244,7 +244,7 @@
   # If no BUILD_NUMBER is set, create a useful "I am an engineering build
   # from this date/time" value.  Make it start with a non-digit so that
   # anyone trying to parse it as an integer will probably get "0".
-  BUILD_NUMBER := eng.$(shell echo $${BUILD_USERNAME:0:6}).$(shell $(DATE) +%Y%m%d.%H%M%S)
+  BUILD_NUMBER := $(TARGET_BUILD_VARIANT).$(shell echo $${BUILD_USERNAME:0:6}).$(shell $(DATE) +%Y%m%d.%H%M%S)
   HAS_BUILD_NUMBER := false
 endif
 .KATI_READONLY := BUILD_NUMBER HAS_BUILD_NUMBER