diff --git a/metropolis/installer/main.go b/metropolis/installer/main.go
index 735a8cd..ecb4d01 100644
--- a/metropolis/installer/main.go
+++ b/metropolis/installer/main.go
@@ -161,7 +161,7 @@
 		return fmt.Errorf("failed to open node parameters from ESP: %w", err)
 	}
 
-	ociImage, err := oci.ReadLayout("/installer/metropolis-installer/osimage")
+	ociImage, err := oci.AsImage(oci.ReadLayout("/installer/metropolis-installer/osimage"))
 	if err != nil {
 		return fmt.Errorf("failed to read OS image from ESP: %w", err)
 	}
diff --git a/metropolis/installer/test/run_test.go b/metropolis/installer/test/run_test.go
index daff8cd..898ad44 100644
--- a/metropolis/installer/test/run_test.go
+++ b/metropolis/installer/test/run_test.go
@@ -156,7 +156,7 @@
 		log.Fatal(err)
 	}
 
-	image, err := oci.ReadLayout(xImagePath)
+	image, err := oci.AsImage(oci.ReadLayout(xImagePath))
 	if err != nil {
 		log.Fatal(err)
 	}