Quickly press the Function key 3 times in 2 seconds, then release the key. You will see the Power LED (Red) blink for about 3 seconds.

After the Power LED (Red) turns OFF, this indicates that the board is in Upgrade Mode (Maskrom Mode).

Refer to Setup Serial Tool to setup your Serial Tool for Edge2.

Once again, make sure you’ve done the correct connections and setup.

Hit SPACE on your keyboard at the moment of bootup to stop autoboot. This step will let Edge2 boot into U-Boot command line.

Type run update in the terminal of U-Boot. The Red LED will turn ON when you’ve entered Upgrade Mode.

Refer to this guide to setup your serial tool for Edge2.

Once again, make sure you’ve done the correct connections and setup.

Boot into Android or Linux command line.

For Linux, execute sudo reboot loader. For Android, execute su and reboot loader. The system will reboot and enter Upgrade Mode. You will see the Red LED turn ON when you’ve entered Upgrade Mode (Loader Mode).