I'm posting this to assist other users of Navionics platinum plus charts. First, the charts are spectacular and allow me to fish new areas. In an attempt to update a new Navionics SD card on my tablet I ran into trouble. The red flag, that I missed, was that the update was very quick. I didn't realize until later that was low on disk space. We go to launch and fire up the charts it became apparent the update did not work, the charts were blurry. I called Navionics and they were very helpful, but wanted to make sure to post this advice. You need to have sufficient disk space when updating the charts or you may find yourself in the same situation. Not sure how much, maybe one of the guru's on the site could chime in.