Disable cloud-init DHCP for static IP setup

autoinstall/firstboot-setup.sh

@@ -83,7 +83,9 @@ NET_MODE=$(whiptail --title "$TITLE" \
   3>&1 1>&2 2>&3)
 
 if [ "$NET_MODE" = "Static" ]; then
-  rm -f /etc/netplan/99-cezen-dhcp.yaml || true
+  mkdir -p /etc/cloud/cloud.cfg.d
+  printf "network: {config: disabled}\n" > /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg
+  rm -f /etc/netplan/50-cloud-init.yaml /etc/netplan/99-cezen-dhcp.yaml || true
 
   IP_ADDR=$(whiptail --title "$TITLE" \
     --inputbox "\nEnter static IP address:\n(Example: 192.168.1.100)" \
@@ -123,6 +125,7 @@ network:
       nameservers:
         addresses: [${DNS}]
 EOF
+  chmod 0600 /etc/netplan/99-cezen-static.yaml
 
   if ! netplan apply; then
     whiptail --title "$TITLE" \