diff --git a/src/pypungi/__init__.py b/src/pypungi/__init__.py
index 9e9d161d..6c65bc92 100644
--- a/src/pypungi/__init__.py
+++ b/src/pypungi/__init__.py
@@ -1608,7 +1608,7 @@ class Pungi(pypungi.PungiBase):
         # NOTE: if this doesn't match what's in the bootloader config, the
         # image won't be bootable!
         extraargs.append('-V')
-        extraargs.append('%s %s %s' % (self.config.get('pungi', 'name'),
+        extraargs.append('%s-%s-%s' % (self.config.get('pungi', 'name'),
             self.config.get('pungi', 'version'), self.tree_arch))
 
         extraargs.extend(['-o', isofile])