diff --git a/tools/testing/selftests/firmware/fw_filesystem.sh b/tools/testing/selftests/firmware/fw_filesystem.sh
index b1f20fef36c77444d3de0730dfb73c223060ac56..f9508e1a4058995098df7cea4b70bc65418a1d34 100755
--- a/tools/testing/selftests/firmware/fw_filesystem.sh
+++ b/tools/testing/selftests/firmware/fw_filesystem.sh
@@ -45,7 +45,10 @@ test_finish()
 	if [ "$HAS_FW_LOADER_USER_HELPER" = "yes" ]; then
 		echo "$OLD_TIMEOUT" >/sys/class/firmware/timeout
 	fi
-	echo -n "$OLD_PATH" >/sys/module/firmware_class/parameters/path
+	if [ "$OLD_FWPATH" = "" ]; then
+		OLD_FWPATH=" "
+	fi
+	echo -n "$OLD_FWPATH" >/sys/module/firmware_class/parameters/path
 	rm -f "$FW"
 	rmdir "$FWPATH"
 }