Add Frida's repository by navigating through the menu: Manage => Sources => Edit => Add
Enter https://build.frida.re
Wait till Cydia reloads the repository.
Find and install the frida package or if you want a specific version of Frida you may download the .deb file from here and install it manually (via SSH) or using an app like iFile
Reboot the device
This should be changed, rebooting device removes jailbreak
This should be changed, rebooting device removes jailbreak