You have never applied for a certificate, have you? Grain Rain is a software that needs to be signed. If you don't have a certificate, you can't apply now, because Nokia has closed the certificate application business and all major websites can't apply. I suggest you go to the software download area of Saipan smartphone forum to find the signing procedure. Baidu's "Saipan Smartphone Forum" is not convenient to give you a link, and the solution can only be like this. Good luck ~