Trouvé et ca marche pour moi attention il faut télécharger la version english du firmware sinon ca sera en chinois
cross-posting from another forum:
1 - Open G+MassProductionTool For GP330XX.exe.
2 - Click open and make sure to choose burning_all_by_usb_OnlyNandPlatform.conf
3 - Connect your s602 to the usb port. Do not turn it on yet.
4 - Press power and start at the same time.
5 - It will ask if you want to add the device. Choose Yes and then Start download.
6 - At the end choose G+MassProductionTool For GP330XX.exe and then unplug the s602
7 - Turn the s602 again and you will need to calibrate the touch screen.
Tks tiagao_extremo, it worked for me!