diff --git a/core/installer/derived.go b/core/installer/derived.go
index cf792ef..4030623 100644
--- a/core/installer/derived.go
+++ b/core/installer/derived.go
@@ -83,7 +83,7 @@
 		// TODO(gio): validate that it is map
 		v, ok := values.(map[string]any)[k]
 		// TODO(gio): if missing use default value
-		if !ok {
+		if !ok || v == nil {
 			if def.Kind() == KindSSHKey {
 				key, err := NewECDSASSHKeyPair("tmp")
 				if err != nil {