following the link I gave you you should be able to read this:
Installation Instructions
1.Click on 'Download' and choose to save the file to your computer.
2.Choose a location where you can easily find the file, such as the 'My Documents' folder or 'C:\'.
3.Once the download is complete, go to the location where you saved the file.
4.Double-click on the downloaded file. This will automatically extract the files to C:\Garmin and run a program to transfer the software update to an SD card.
5.Power on the device and make sure all other connected devices are powered on as well.
6.Insert the card into the card slot of your primary device. Select 'Update Software' in the window that automatically displays. If you do not have a primary device with a card slot, please see your dealer.
7.After the update completes, the chartplotter containing the SD card and all NMEA 2000 sensors will have the latest software. Note: If you have additional chartplotters connected to NMEA 2000, you will have to independently update each chartplotter. After the update completes, insert the update card into each NMEA 2000 chartplotter.
;)
18th January 2011, 02:37 PM
gpshacker123
Hi, yes I overlooked that information because I directly clicked on the GPS model number and it took me to a different page. Obviously I was doing the update procedure wrong, as I was inserting the card before turning on the GPS, not after. I'll try again and hope it works. Thanks.
26th January 2011, 10:32 PM
gpshacker123
Hi, I did the procedure correctly this time and I was able to update firmware with the 1GB card, no issues. I just turned the unit on, and THEN inserted the card with the update to v5.5 and all went well. Thank you for an excellent source of good information!