diff --git a/builder/main.py b/builder/main.py
index 560b9fa..2e58fe6 100644
--- a/builder/main.py
+++ b/builder/main.py
@@ -134,13 +134,19 @@
         else:
             encrypt_message = "Encrypting $TARGET with default key"
 
+        # Choose the correct board name for teensy_secure
+        if board_config.id == "teensymm":
+            board_name = "TEENSY_MICROMOD"
+        else:
+            board_name = board_config.id.upper()
+
         env.Append(
             BUILDERS=dict(
                 HexToEhex=Builder(
                     action=env.VerboseAction(" ".join([
                         "$TEENSYSECURE",
                         "encrypthex",
-                        board_config.id.upper(),
+                        board_name,
                         "$SOURCES",
                         custom_secure_key
                     ]), encrypt_message),