diff --git a/make/defs.mk b/make/defs.mk
index 4955b23d..966a2d59 100644
--- a/make/defs.mk
+++ b/make/defs.mk
@@ -144,7 +144,7 @@ endef
 # ----- standard variables
 
 ifeq ($(PROJECT),)
-  PROJECT                   := $(shell $(ECHO) $(patsubst $(FLAVOUR_PREFIX)%,%,$(notdir $(realpath $(TOPDIR)))) | $(SED) 's/-[0-9].*//')
+  PROJECT                   := $(shell $(ECHO) $(patsubst $(FLAVOUR_PREFIX)%,%,$(notdir $(realpath $(TOPDIR)))) | $(SED) 's/-[0-9]\+\..*//')
 endif
 
 ifneq ($(wildcard $(TOPDIR)/.git),)