diff --git a/uncloud/hack/main.py b/uncloud/hack/main.py
index 9607ec2..a0c3ca6 100644
--- a/uncloud/hack/main.py
+++ b/uncloud/hack/main.py
@@ -30,6 +30,7 @@ arg_parser.add_argument('--list-vms', action='store_true')
 arg_parser.add_argument('--memory', help="Size of memory (GB)", type=int)
 arg_parser.add_argument('--cores', help="Amount of CPU cores", type=int)
 arg_parser.add_argument('--image', help="Path (under hackprefix) to OS image")
+arg_parser.add_argument('--image-format', help="Image format: qcow2 or raw", choices=['raw', 'qcow2'])
 arg_parser.add_argument('--uuid', help="VM UUID")
 
 arg_parser.add_argument('--no-db', help="Disable connection to etcd. For local testing only!", action='store_true')
diff --git a/uncloud/hack/vm.py b/uncloud/hack/vm.py
index d86941b..b38d563 100755
--- a/uncloud/hack/vm.py
+++ b/uncloud/hack/vm.py
@@ -59,18 +59,23 @@ class VM(object):
         self.uuid = self.config.arguments['uuid']
         self.memory = self.config.arguments['memory'] or '1024M'
         self.cores = self.config.arguments['cores'] or 1
+
         if self.config.arguments['image']:
             self.image = os.path.join(self.hackprefix, self.config.arguments['image'])
         else:
             self.image = None
 
+        if self.config.arguments['image_format']:
+            self.image_format=self.config.arguments['image_format']
+        else:
+            self.image_format='qcow2'
+
         # External components.
         self.vmm = VMM(vmm_backend=self.hackprefix)
         self.mac = MAC(self.config)
 
         # Harcoded & generated values.
         self.owner = 'uncoud'
-        self.image_format='qcow2'
         self.accel = 'kvm'
         self.threads = 1
         self.ifup = os.path.join(self.hackprefix, "ifup.sh")