diff --git a/README.MD b/README.MD
index 3eba704..ad0290a 100644
--- a/README.MD
+++ b/README.MD
@@ -1,6 +1,13 @@
 ## Updating Instruction
 
-Do not edit 'net.retrodeck.mame.yml'
-This file is automatically generated from 'mame-module.yml' and 'manifest-header.yml'
-Any changes to 'net.retrodeck.mame.yml' will be discarded.
-Please update 'mame-module.yml' and 'manifest-header.yml' instead.
+Do not edit `net.retrodeck.mame.yml` nor `manifest-header.yml`:
+
+These files are automatically generated by `automation_tools/update_mame_manifest.sh`.
+
+`manifest-header.yml` is generated from the RetroDECK manifest itself, mind that:
+- any changes to `net.retrodeck.mame.yml` will be discarded.
+- any changes to `manifest-header.yml` will be discarded.
+
+Then `manifest-header.yml` + the editable `mame-module.yml` are combined into `net.retrodeck.mame.yml`.
+
+So please update `mame-module.yml` only.