You can connect your bluetooth joystick manually.
You will need root access for this.
Put your bluetooth joystick in association mode and type:
This will get the joystick's mac address:
aa:bb:cc:dd:ee:ff Name:Bluetooth HID
Then create the connection to the joystick:
hidd --connect aa:bb:cc:dd:ee:ff
And restart Emulationstation:
You have two options. One may not work, if it does, try the next one. Start your controller in pairing mode, make sure you have previously reset it and removed any existing associations. Attention: for now, you must start your Bluetooth control after EmulationStation is started.
Find your control's mac address (in capital format) using:
Try several times if your controller does not appear on the list. If, after a few attempts, your control is still not listed, go to method B.
If your controller is listed, type:
/recalbox/scripts/bluetooth/simple-agent hci0 "AA:BB:CC:DD:EE:FF"
Where AA: BB: CC: DD: EE: FF is your device's mac address in uppercase. A PIN code may be requested, see the documentation for your joystick. If you are still unable to pair, try the next method.
bluetoothctl and type the following commands:
agent ondefault-agentpower onscan on
bluetoothctl lists your device and:
pair AA:BB:CC:DD:EE:FFconnect AA:BB:CC:DD:EE:FFtrust AA:BB:CC:DD:EE:FF