diff --git a/builder/main.py b/builder/main.py
index a7af5c5..4d7bbf8 100644
--- a/builder/main.py
+++ b/builder/main.py
@@ -330,7 +330,7 @@ elif upload_protocol in debug_tools:
     upload_actions = [env.VerboseAction("$UPLOADCMD", "Uploading $SOURCE")]
 
 # custom upload tool
-elif "UPLOADCMD" in env:
+elif upload_protocol == "custom":
     upload_actions = [env.VerboseAction("$UPLOADCMD", "Uploading $SOURCE")]
 
 else: