I have a 76 cx and a borrowed blue chart micro sd card that works great. I copy card run garmingmapsupp.img which produces a unlocked image and a locked image. I remove the locked image from the original download and replace it with the unlocked image and copy to a new 256mb micro sd, install it in the unit and it does not recognize it. Remove it and reinstall the org sd card and it works perfect. I also copied a g2 vision with the same results. I have not read the entire forum but I have read many hours to find the solution with no results. Please help