diff --git a/metropolis/node/build/mkimage/main.go b/metropolis/node/build/mkimage/main.go
index 3695054..3a68fc7 100644
--- a/metropolis/node/build/mkimage/main.go
+++ b/metropolis/node/build/mkimage/main.go
@@ -100,7 +100,7 @@
 	cfg.ABLoader = bytes.NewReader(abloader)
 
 	// Write the parametrized OS image.
-	if _, err := osimage.Create(&cfg); err != nil {
+	if _, err := osimage.Write(&cfg); err != nil {
 		log.Fatalf("while creating a Metropolis OS image: %v", err)
 	}
 }