diff --git a/metropolis/node/build/mkimage/osimage/osimage.go b/metropolis/node/build/mkimage/osimage/osimage.go
index 4ad2d5f..2f000a6 100644
--- a/metropolis/node/build/mkimage/osimage/osimage.go
+++ b/metropolis/node/build/mkimage/osimage/osimage.go
@@ -21,7 +21,6 @@
 import (
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 
 	diskfs "github.com/diskfs/go-diskfs"
@@ -58,7 +57,7 @@
 	// If this is streamed (e.g. using io.Copy) it exposes a bug in diskfs, so
 	// do it in one go.
 	// TODO(mateusz@monogon.tech): Investigate the bug.
-	data, err := ioutil.ReadAll(src)
+	data, err := io.ReadAll(src)
 	if err != nil {
 		return fmt.Errorf("while reading %q: %w", src, err)
 	}