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I am confused. I tried two SDrive² with additional SIO connector and both refused to work with my 800XL. After turning the computer on, the red and green LED consecutively flash and then the four yellow LEDs turn on. But the computer does not boot to the configuration menu. I can hear the characteristic buzzing noise indicating no drive being attached and eventually end up with the self test. I did some tests to verify that it is not a general problem with the SIO port of my computer: 1) Only SDrive² attached to computer → does not boot 2) Only 1050 attached to computer → boots from disk 3) Only SDrive-MAX attached to computer → boots to SDrive configuration menu 4) SDrive² attached to computer, 1050 attached to SDrive² → boots from disk 5) SDrive² attached to computer, SDrive-MAX attached to SDrive² → does not boot 6) SDrive² attached to 1050 → boots from disk What can bring this behaviour on?