diff --git a/appimagebuilder/modules/prime/appimage_primer.py b/appimagebuilder/modules/prime/appimage_primer.py
index 26be973..4bd3614 100644
--- a/appimagebuilder/modules/prime/appimage_primer.py
+++ b/appimagebuilder/modules/prime/appimage_primer.py
@@ -166,7 +166,7 @@ def _patch_appimage(self, offset, data):
 
     def _generate_zsync_file(self):
         if self.config["update-information"]:
-            zsyncmake_bin = shutil.which("zsyncmake")
+            zsyncmake_bin = shell.require_executable("zsyncmake")
             command = [
                 zsyncmake_bin,
                 "-u",