Best way (fast) is to connect to Netview via USB. Top screen has a update firmware and select the latest. Not stable. Or you can do it the slow way and connect to base with your LS+ under remote base. Click on the window below start/stop base or above where you put in the base coords (small rectangle). Update firmware. This way downloads the file to the LS+ then sends file via Bluetooth (slow) to the T3. You may have to do this a few times before it works.