@substring problem solved after a reboot I just had to hold down the "home + x" buttons. classical user error but, thank you for your helpfulness

@substring yes, if I do a reboot of the raspberry, all controller settings (configuration) are lost and I have to set up the controller again in the emulation station.

greetings from germany

at first the hardware and software information:
main hardware: Raspberry pi 2 B
bluetooth dongle: CSL - V4.0 USB nano Bluetooth Adapter avec DEL Class 4.0
OS: recalbox 4.1 with latest updates (stable)
gamepad: ACGAM Red Spider Bluetooth Controller (AG-9055) -- similar to the Ipega PG-9055 controller?

the situation:
i copied the "99-joysticks-exotics.rules" from here
(https://github.com/recalbox/recalbox-buildroot/tree/master/board/recalbox/fsoverlay/etc/udev/rules.d)
to my
(RECALBOX\system\udev\rules.d)

after that, the controller was successfully paired as a gamecontroller with the mac address (aa:bb:cc:dd:ee:ff AG-9055).
i configured the controller also successfully and completly with all buttons. then the controller function was perfectly when i defiend it at (input p1) as "#0 AG-9055" at the menu point "controller settings" .

and now the problem:
the controller settings will not be saved when the recalbox was shut down or restarted.

additional information:
in the "recalbox.conf" , the input driver was set to this:

Set retroarch input driver (auto, udev, sdl2)
If you don't have issues with your controllers, let auto
global.inputdriver=sdl2

any other options (auto or udev) make the controller not working as requested / defiend . for example in the snes emulator.