Hi, i had the same problem. After changing the battery, firstly the watch has started. So i have let the watch until the battery was empty and charged it. After a night of charging trying to start the watch : green snake !
So i have let the watch during one week without recharging it. Then i have put the watch on the charger during 2 hours and the watch had started by itself and now all is ok.
DOESN'T WORK FOR ME : Have followed the guide in every point but i have now the red snake.
Just after repairing i put the watch on the charger, let it some hours to charge.
when I took it, the watch was hot. It started up and was working. I let it discharge then put it back on the charger. After a few hours, it was not charged and showed the green snake. When I took it out, it showed the red snake.