diff --git a/internal/internal.go b/internal/internal.go
index dd6142a..b4ecd61 100644
--- a/internal/internal.go
+++ b/internal/internal.go
@@ -175,9 +175,15 @@
 // GenPath reports the directory in which to store generated files.
 func GenPath(root string) string {
 	info, err := os.Stat(filepath.Join(root, "cue.mod"))
-	if err == nil && info.IsDir() {
-		// TODO(legacy): support legacy cue.mod file.
-		return filepath.Join(root, "cue.mod", "gen")
+	if os.IsNotExist(err) || !info.IsDir() {
+		// Try legacy pkgDir mode
+		pkgDir := filepath.Join(root, "pkg")
+		if err == nil && !info.IsDir() {
+			return pkgDir
+		}
+		if info, err := os.Stat(pkgDir); err == nil && info.IsDir() {
+			return pkgDir
+		}
 	}
-	return filepath.Join(root, "pkg")
+	return filepath.Join(root, "cue.mod", "gen")
 }