diff --git a/scripts/run_signature.py b/scripts/run_signature.py
index 8b7060ff5..833686cf3 100755
--- a/scripts/run_signature.py
+++ b/scripts/run_signature.py
@@ -16,7 +16,7 @@
 
 
 def run_with_cocotb(test_name: str, traces: bool, output: str) -> bool:
-    arglist = ["make", "-C", parent + "/test/regression/cocotb", "-f", "signature.Makefile", "--no-print-directory"]
+    arglist = ["make", "-C", parent if parent else "" + "/test/regression/cocotb", "-f", "signature.Makefile", "--no-print-directory"]
 
     if os.path.isfile(output):
         os.remove(output)