The steps of signing online are super simple, which I have always done:
1. Log in to Eurocool.
2. Find the application for Saipan certificate
3. Register an account to log in under the page (you can always use the same account after registering once), and then submit the IMEI code to apply for the certificate.
4. After the certificate is generated the next day, check the certificate that has been successfully applied.
5. If the software that needs to be signed cannot be installed normally, you will be prompted that the certificate is wrong or expired. Go to the "online signing software" to upload the software, click OK, it will be completed in a few seconds, and then download it to the computer.
6. Just copy the signed software to your mobile phone and install it.
SIS or SISX refers to the format suffix of the software you downloaded. If you can't find it, it means that you haven't downloaded the special program software for S60. The suffix of JAVA software is generally JAR or JAD.
Ouku's software channel has a lot of daily practical software. You can also find them. There must be a program you need. That's where I found the software I needed.