diff --git a/utils/checkpackagelib/lib_mk.py b/utils/checkpackagelib/lib_mk.py
index 0278354434..572fe75990 100644
--- a/utils/checkpackagelib/lib_mk.py
+++ b/utils/checkpackagelib/lib_mk.py
@@ -77,7 +77,7 @@ class Indent(_CheckFunction):
 
 
 class OverriddenVariable(_CheckFunction):
-    CONCATENATING = re.compile(r"^([A-Z0-9_]+)\s*(\+|:|)=\s*\$\(\\1\)")
+    CONCATENATING = re.compile(r"^([A-Z0-9_]+)\s*(\+|:|)=\s*\$\(\1\)")
     END_CONDITIONAL = re.compile(r"^\s*({})".format("|".join(end_conditional)))
     OVERRIDING_ASSIGNMENTS = [':=', "="]
     START_CONDITIONAL = re.compile(r"^\s*({})".format("|".join(start_conditional)))