It’s been a few years since I did the upgrade, so I am not up to date on the update procedure, so this info may not be 100% correct. I used a San disk card, preferably one that is 256mb or less, I used a 128mb. I was cautioned that the processor in the C80 does not work well with larger cards. In years past you were able to buy cards for a general region, ie. Gulf Coast, Southern Florida & Bahamas. Now you basically purchase the entire US & Bahamas and select the regions that you desire up to the capacity of your card. Again, don’t go over 256mb cause it isn’t going to work on the C80. Once you download the data from Navionics onto your computer and onto the card, simply install the card in your C80 . Beware that you have to update the firmware on the C80 before upgrading to the new charts. That involves a free download from Raymarine onto a separate cf card (64mb card) and installing the upgrade on the C80, prior to installing the new charts. The final firmware update was a few years ago, and Raymarine has discontinued any further updates. I don’t have that update volume number readily available. I think that there are instructions for each procedure on the net and possibly on you tube. I had the good fortune of finding a new navionics cf card reader, several years ago, on EBay. You might try there; however, they are very difficult to find. I purchased the navionics chart update from landfall navigation.
