Here you will find updates for your XTreme EFIS and EMS Generation 1 units. 

If you have a Generation 2 unit please check the Gen 2 XTreme Update page here

You can tell the difference by looking at the version number at startup. If you have a generation 1 unit the version number will be 1.XX. Generation 2 units have version numbers 2.XX.

You will need a freshly formatted full-size SD card to accomplish this update. 

Download the EFIS/EMS update packages to complete the update (instructions enclosed in the package).