diff --git a/templates/830_network-interfaces-legacy.yaml.tt2 b/templates/830_network-interfaces-legacy.yaml.tt2
index d2730f6..823d17f 100644
--- a/templates/830_network-interfaces-legacy.yaml.tt2
+++ b/templates/830_network-interfaces-legacy.yaml.tt2
@@ -6,7 +6,7 @@ file:
     owner: root
     group: root
     filetype: file
-    contains: ['/^GRUB_CMDLINE_LINUX_DEFAULT=".*net.ifnames=0.*"/']
+    contains: ['!/^GRUB_CMDLINE_LINUX_DEFAULT=".*net.ifnames=0.*"/']
 
 command: