diff --git a/dragonflybsd/Makefile b/dragonflybsd/Makefile
index c83cbcd..6b50a3b 100644
--- a/dragonflybsd/Makefile
+++ b/dragonflybsd/Makefile
@@ -1,3 +1,5 @@
+ISO=dfly-x86_64-5.2.1_REL.iso
+
 .PHONY: install-boxes install-box-virtualbox
 
 all: install-boxes
@@ -7,8 +9,14 @@ install-boxes: install-box-virtualbox
 install-box-virtualbox: dragonflybsd-virtualbox.box
 	vagrant box add -f --name mcandre/dragonflybsd --provider virtualbox dragonflybsd-virtualbox.box
 
-dragonflybsd-virtualbox.box: dragonflybsd.json http/p *.sh Vagrantfile
-	PACKER_LOG=1 packer build -force -only virtualbox-iso dragonflybsd.json
+$(ISO).bz2:
+	wget https://mirror-master.dragonflybsd.org/iso-images/$(ISO).bz2
+
+$(ISO): $(ISO).bz2
+	bunzip2 $(ISO).bz2
+
+dragonflybsd-virtualbox.box: dragonflybsd.json $(ISO) http/p *.sh Vagrantfile
+	PACKER_LOG=1 packer build -force -only virtualbox-iso -var 'iso=$(ISO)' dragonflybsd.json
 
 clean: clean-boxes clean-vagrant clean-artifacts clean-isos
 
diff --git a/dragonflybsd/dragonflybsd.json b/dragonflybsd/dragonflybsd.json
index c827609..dbd6fee 100644
--- a/dragonflybsd/dragonflybsd.json
+++ b/dragonflybsd/dragonflybsd.json
@@ -1,10 +1,13 @@
 {
+  "variables": {
+    "iso": ""
+  },
   "builders": [
     {
       "type": "virtualbox-iso",
       "guest_os_type": "FreeBSD_64",
       "vm_name": "dragonflybsd",
-      "iso_url": "http://mirror-master.dragonflybsd.org/iso-images/dfly-x86_64-5.2.0_REL.iso",
+      "iso_url": "{{user `iso`}}",
       "iso_checksum_type": "md5",
       "iso_checksum_url": "http://avalon.dragonflybsd.org/iso-images/md5.txt",
       "ssh_username": "vagrant",