Update README.md

README.md

@@ -58,12 +58,15 @@ Tested with the XBOX 360 Gamepad.
 
 ## Installation
 
-After your installation, independent of the method, you should add yourself
-to the `input` and `plugdev` groups so that you can read information from your
-devices. You have to start the application via sudo otherwise.
+The tool shows and logs if there are issues, but usually, independent of the
+method, you should add yourself to the `input` and `plugdev` groups so that
+you can read information from your devices. You have to start the application
+via sudo otherwise. You may also need to grant yourself write access to
+`/dev/uinput` to be able to inject your programmed mapping.
 
 ```bash
 sudo usermod -a -G plugdev,input $USER
+sudo setfacl -m u:$USER:rw- /dev/uinput
 # log out and back in or restart, the two groups should be visible with:
 groups
 ```