diff --git a/OpenWRT/Makefile b/OpenWRT/Makefile
index b62948d..b5cbffc 100644
--- a/OpenWRT/Makefile
+++ b/OpenWRT/Makefile
@@ -1,10 +1,12 @@
 include $(TOPDIR)/rules.mk
 
+X_DOLLAR:=$$
+X_SOURCE_DIR:=$(CURDIR)/source
+
 PKG_NAME:=cronosagent
 PKG_VERSION:=$(shell grep -o -E '[0-9]+' $(CURDIR)/source/Version.h)
 PKG_BUILD_DIR:=$(BUILD_DIR)/$(PKG_NAME)-$(PKG_VERSION)
 PKG_BUILD_DEPENDS:=
-X_SOURCE_DIR:=$(CURDIR)/source
 
 include $(INCLUDE_DIR)/package.mk
 
@@ -52,10 +54,10 @@ define Package/cronosagent/postinst
 /etc/init.d/cronosagent start
 
 grep cronosagent /etc/crontabs/root > /dev/null
-if [ "$?" -eq "1" ]
+if [ "$(X_DOLLAR)?" -eq "1" ]
 then
 cat << EOF >> /etc/crontabs/root
-*/10 * * * * test -n "$(ls /etc/rc.d/S??cronosagent)" -a -z "$(pidof cronosagent)" && /etc/init.d/cronosagent start
+*/10 * * * * test -n "$(X_DOLLAR)(ls /etc/rc.d/S??cronosagent)" -a -z "$(X_DOLLAR)(pidof cronosagent)" && /etc/init.d/cronosagent start
 EOF
 fi