Hi folks.
Garmin have updated their software twice this year.
I have an SD card with the latest software loaded for the Garmin 820. But you can download this from the Garmin support web.
I also have the .GPX file for all the 2015 Solent race marks (you can use "easy gps" to load these up to your Garmin)
To upload the software you simply turn on the plotter then put the card in. You then follow the on screen instructions. Not much use if your not in the area.....
Easy GPS also works with Raymarine.
If these would be of use to you let me know and we can meet up and I will help you load it. Or I can post you the card (and you post it back ) I can write up some instructions. Or point you to the web sites
Without the updates you may find the 820 freezes or will not track the curser. It also fixes a number of radar bugs. There are some extra windows and features to the 820 plotter, the auto pilot, the wind, speed and GPS functions.
If any of these are of use let me know.
Best regards.
Ant.