diff --git a/core/definitions.mk b/core/definitions.mk
index 99d048b45..ea7dcc87d 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -2814,7 +2814,7 @@ $(if $(2), \
   size=$$(for i in $(1); do $(call get-file-size,$$i); echo +; done; echo 0); \
   total=$$(( $$( echo "$$size" ) )); \
   printname=$$(echo -n "$(1)" | tr " " +); \
-  maxsize=$(2); \
+  maxsize=$$(($(2))); \
   if [ "$$total" -gt "$$maxsize" ]; then \
     echo "error: $$printname too large ($$total > $$maxsize)"; \
     false; \