The certificate may have expired. When installing the software, you can adjust the date of the phone to previous years. I suggest you jailbreak your phone. You need to use Safe Manager (because this software has a certificate with 20 permissions, no signature is required, and it can be installed directly) and then installserver.exe (this is a visa-free file. I saw that your phone is FP2, and this visa-free file is also FP2 only), use the installed "Security Manager" to put it in C:SYS/Bin. I will send it to you later, and then download the "deep crack" installation yourself (if installserver.exe is not placed in C:SYS/ Bin, a certificate error will be prompted during installation.) After installing the deep crack, you can only click on the second patch (OPEN4ALL, remember to turn on the auto-start of this patch) and then your phone will be cracked and you can say goodbye to the certificate. If there are still software that cannot be installed, use "free signature" to remove the software signature and then install it. If there is software that cannot be installed, it is a problem with the software itself. Remember to add points, and remember to promote it. That installserver.exe can only be used for FP2 phones (otherwise it will prompt that the file is damaged when installing the software). Other FP1 and MR have their own.

Welcome to ask questions