To use the Helix data in a SOLIX, load them to HumminbirdPC. Then click on the new file name to highlight it blue. Then at the top left FILES, select SAVE AS GPX to a memory card, put the card in the SOLIX to load it to the unit's waypoint library.
You cannot copy the map data and no you cannot use a SD card in a microSD reader.
Navionics has used microSD cards since 2010, have you looked at the card to see if it is microSD in a SD adapter. Black cards are SD adapters.