diff --git a/script/trees b/script/trees
index 8bf0369..443c670 100755
--- a/script/trees
+++ b/script/trees
@@ -288,7 +288,7 @@ mkpayload_grub()
 
 copy_elf()
 {
-	[ -z "$listfile" ] && return 0
+	[ -f "$listfile" ] || return 0
 
 	while read -r f; do
 		[ -f "$cdir/$f" ] && x_ cp "$cdir/$f" "$dest_dir"