A. G-chart updates and upgrades must be done directly with GARMIN. Please call 1-800-800-1020 for assistance. An "update" refers to a new issue date of a chart. The cartridge number, size, and coverage area must remain the same. The G-chart buyer protection policy entitles the buyer to return the chart for a free "update" within 90 days of purchase if one occurs. After 90 days a G-chart "update" will be 50% of the new purchase price. An "upgrade" occurs when a new chart with a new part number is introduced for an area. GARMIN will accept any old chart as a trade-in for 25% off the price of a new chart. Only one trade-in per chart is allowed.