1. The software has not been signed.

After applying for the certificate yourself, you can sign and install it. Generally, there are places to apply for signatures on Saipan forums.

2. The software has been signed by others.

Use signature software to remove other people's signatures and then sign and install them yourself.

3. Turn off online certificate checking and set the installation type to all.

In the phone settings.

4. When the mobile phone is installed, it will prompt that the certificate has expired or failed to take effect.

Adjust the mobile phone time to the certificate time limit before installation.

5. No signature is required to install any software after directly cracking the installation authority of the mobile phone.

Saipan forum has a cracking tutorial.

Pure hand tour, I hope to help you!