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Tested with Xu4 and Xu4Q Using Retropie
This bluetooth adapter was tested to link to a PS3 Bluetooth Controller in Retropie ( worked fine)
It did require a few attempts to pair.
This bluetooth adapter would not work with the new gamesir 4 controller.
Retropie is very much trial and error. The adapter did pair with a PS3 bluetooth Controller and did work flawless in retropie.
Anything else will be hit and miss.
Plug n Play NO Setup On This Adapter