Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
To do the firmware update you were recommended to do, simply take your computer, put Garmin Express software on it (instructions follow), and then start that software, and then connect your Garmin device to the computer with a USB cable, and then do the updating once the Garmin device is recognized by the software.
Here are the instructions:
Simply download, install, and use Garmin Express.
and (if you have a Windows PC) click on the big blue Download button at center bottom of the page. (If you have an Apple, click on the nearby Download for Mac link.) And download Garmin Express' installer to your computer, save it, then double-click upon it to install Garmin Express.
Then start the program, Garmin Express. Then connect your Garmin device. Then use Garmin Express to update your device.
Let me know whether that helps... or not. If not, I will have further advice to offer. If so, I will be able to close this case, if what I recommended helps. Thanks.