In four easy steps:
Use a USB jump/flash/thumb drive (32GB or less, formatted as FAT32).
Make sure it is a clean Flash drive before starting (nothing else on it).
1) Download the TZT3 software from the Furuno website to a folder on your desktop.
2) Once you download the Zip file, you will need to extract it.
3) Transfer the unzipped folders and files to the root directory of a USB Flash drive.
4) With the TZT3 unit OFF, insert the created USB program stick into the “USB1 Port”
Then... power the TZT3 On.