diff --git a/script/trees b/script/trees
index d0fba24..b197314 100755
--- a/script/trees
+++ b/script/trees
@@ -289,6 +289,7 @@ mkpayload_grub()
 
 copy_elf()
 {
+	[ -n "$listfile" ] || return 0
 	[ -f "$listfile" ] || return 0
 
 	while read -r f; do