The wiki mentioned two methods:
/recalbox/scripts/bluetooth/test-device list
8C:CD:E8:73:F4:87 Nintendo RVL-CNT-01-UC
/recalbox/scripts/bluetooth/simple-agent hci0 "8C:CD:E8:73:F4:87"
Agent registered
Creating device failed: org.bluez.Error.AlreadyExists: Already Exists
[bluetooth]# pair 8C:CD:E8:73:F4:87
Attempting to pair with 8C:CD:E8:73:F4:87
Failed to pair: org.bluez.Error.AlreadyExists
[bluetooth]# connect 8C:CD:E8:73:F4:87
Attempting to connect to 8C:CD:E8:73:F4:87
[CHG] Device 8C:CD:E8:73:F4:87 Connected: yes
Connection successful
[CHG] Device 8C:CD:E8:73:F4:87 ServicesResolved: yes
[Nintendo RVL-CNT-01-UC]# trust 8C:CD:E8:73:F4:87
Changing 8C:CD:E8:73:F4:87 trust succeeded
-> now the controller is connected
After reboot it can't connect again.
No progress...