Update preinstall.md

docs/guides/preinstall.md

@@ -68,6 +68,9 @@ While the installation image is being written to the USB, you can skip to [Copy
 
 ## Copy Wi-Fi firmware
 
+!!! Warning "Arch/EndeavourOS"
+    If you're going to install Arch or EndeavourOS, you do not need to follow this guide.
+
 Linux's Wi-Fi driver uses the same Wi-Fi firmware files as macOS, so we copy these files from macOS to the EFI partition where Linux can access and eventually install them.
 
 [Follow here](https://wiki.t2linux.org/guides/wifi-bluetooth/#on-macos) the **first part in macOS** and come back to this page.