have you genuine daughterboard? buster? 7? have you experienced lockups previously, when you were running the setup with deneb for the first time? unfortunatelly a3k is a little bit rare, so hard to say if deneb has been tested well with that model, but i dont suspect any serious bugs left. you can set your deneb to zorro2 operation mode via jumper setting, just look at the board, its described there. zorro2 should be the safest mode. still lockups?