diff --git a/fw_updater_packer_unpacker/README.md b/fw_updater_packer_unpacker/README.md
index 64b7290..bd7fddf 100644
--- a/fw_updater_packer_unpacker/README.md
+++ b/fw_updater_packer_unpacker/README.md
@@ -1,3 +1,5 @@
+This doc assumes to be a MacOS. Linux may have GNU commands that differ from the BSD ones. 
+
 # 0x0 Allow your DPT to accept PKG without correct key
 
 This will create SECURITY FLAW in your system!