I think I can help you, I own a Helix 9 si mega. I have a ZLC card in one slot with Live Autochart going to it. Then I have a formatted SD card in the other slot. I will record sonar recordings on the other SD card. Just don't make really long recordings, as if there is a problem you won't waist the whole recording. I am sure that a few others will chime in and elaborate, but that's it in a nut shell. Oh yea you have to tell the unit where to put the Live Autochart data at.