diff --git a/rootfs.py b/rootfs.py
index a9802a92..48ede4a4 100755
--- a/rootfs.py
+++ b/rootfs.py
@@ -177,6 +177,10 @@ def main():
     else:
         args.swap = 0
 
+    # Validate mirrors
+    if not args.mirrors:
+        raise ValueError("At least one mirror must be provided.")
+
     # Set constant umask
     os.umask(0o022)