Amazing Khadas, always amazes you!
There are 5 ways to boot into upgrade mode:
Functionkey 3 times in 2 seconds, then release the key. You will see the Power LED (Blue) blink for about 3 seconds.
POWERkey without releasing it.
Resetkey and release it.
POWERkey to enter into Upgrade Mode. You will see the sys-led turn ON when you’ve entered Upgrade Mode.
SPACEon your keyboard at the moment of bootup to stop autoboot. This step will let Edge1 boot into U-Boot command line.
run updatein the terminal of U-Boot. The Sys LED (White) will turn ON when you’ve entered Upgrade Mode.
run maskromon the terminal of U-Boot as below, and you will enter Maskrom Mode.