Factorio Forums

The game detecting the steam deck as Xbox is a known minor issues. Vast majority of Steam deck verified games actually show Xbox icons.

As for the back buttons (L4, L5, R4, R5) not working, it appears Steam Input does not let me map them to "paddles", which are often extra buttons on a controller. So to use them you need to go into the Steam Input layout configuration and map them yourself to custom controller combinations, or keyboard keys which you then need to map in-game.

Hi! Thanks for great controller support. Will back buttons (L4, L5, R4, R5) issue will be resolved before stable release or it is better to search solution on users side ?

As far as I can tell, this is a software limitation of the Steam Deck.
The game natively supports the back buttons(paddles) on some controllers(such as Xbox Elite) but the Steam Deck input system doesn't support them. You can try editing the layout on the Steam Deck and notice that there's no way to map "paddles" to the back buttons.
Since the game has to go through the Steam Input layout system and does not have direct access to the hardware buttons, it's not possible to use them properly for now.

As a workaround you can map them to keyboard buttons in Steam Input and then also map them in Factorio to the same keys, since the game allows mixing controller, keyboard and mouse inputs for most controls.