diff --git a/Makefile b/Makefile
index c119020..cb1422c 100644
--- a/Makefile
+++ b/Makefile
@@ -44,9 +44,9 @@ setup-weston:
 
 .PHONY: setup-rasp-config
 setup-rasp-config:
-	if [ ! -z $(grep "include forge-invar.txt" "/boot/firmware/config.txt") ]; then sudo sh -c 'echo \"include forge-invar.txt\" >> /boot/firmware/config.txt'; fi
+	if [ -z $(shell grep "include forge-invar.txt" "/boot/firmware/config.txt") ]; then sudo sh -c 'echo "include forge-invar.txt" >> /boot/firmware/config.txt'; fi
 	sudo cp -f $(PWD)/system/config.ini /boot/firmware/forge-invar.txt
-	if [ ! -z $(grep "vc4.tv_norm" "/boot/firmware/cmdline.txt") ]; then sudo sh -c 'echo \"vc4.tv_norm=PAL\" >> /boot/firmware/cmdline.txt'; fi
+	if [ -z $(shell grep "vc4.tv_norm" "/boot/firmware/cmdline.txt") ]; then sudo sh -c 'echo "vc4.tv_norm=PAL" >> /boot/firmware/cmdline.txt'; fi
 
 .PHONY: setup-services
 setup-services: