I've installed the LinuxSatSupport Addon in my VU+ Duo2 and my card is in the top slot. When I had Blackhole I would do this: Select "Cams - BlackHole 2.x.x". Select "Oscam rev 8639 + CCcam 2.1.3". Then I would restart and my Sly card would be read I could view Sly standard definition channels. My card is paired to a standard definition Sly box.
I've done the same thing in Vix but I selected Cams > OpenVix > OSCam svn11160 - CCcam 2.3.0. I can't see the Sly channels. I got my card recently from Sly. It has a white back on the chip side. The other side is red and purple.