diff --git a/Makefile.include b/Makefile.include
index 0e3ac750a2..e113b6a8f4 100644
--- a/Makefile.include
+++ b/Makefile.include
@@ -74,7 +74,7 @@ ifeq ($(origin RIOT_VERSION), undefined)
       RIOT_VERSION := $(GIT_STRING)-$(GIT_BRANCH)
     endif
   else
-    RIOT_VERSION := UNKNOWN
+    RIOT_VERSION := UNKNOWN (builddir: $(RIOTBASE))
   endif
 endif
 export CFLAGS += -DRIOT_VERSION='"$(RIOT_VERSION)"'