This is said in the manual:
"TIP! The supported Bluetooth version is
Bluetooth 3.0 and certified by Bluetooth
SIG. It is compatible with other Bluetooth
SIG certified devices."
That means the LG Optimus 2x has bl 3.0, i think?
So I don't know why tha gamepad doesn't find the LG, without any apps for example Bluez IME or BlueInput...