diff --git a/dkms-install.sh b/dkms-install.sh
index c7c500e..547a6f4 100755
--- a/dkms-install.sh
+++ b/dkms-install.sh
@@ -20,7 +20,7 @@ RESULT=$?
 
 echo "Finished running dkms install steps."
 
-if defined(CONFIG_DISABLE_IPV6)
+if grep -q -e "^CONFIG_DISABLE_IPV6 = y$" "$DRV_DIR/Makefile" ; then
 	if echo "net.ipv6.conf.all.disable_ipv6 = 1
   net.ipv6.conf.default.disable_ipv6 = 1
   net.ipv6.conf.lo.disable_ipv6 = 1" >> /etc/sysctl.conf; then
@@ -29,6 +29,6 @@ if defined(CONFIG_DISABLE_IPV6)
 	else
 		echo "Could not disable IPv6"
 	fi
-endif
+fi
 
 exit $RESULT