If you ever stuck in a poor or unsatisfactory performance after performing a firmware upgrade, you may want to consider Tiny Umbrella to roll back to previous firmware on your devices. Previously, Apple has introduced more restriction in later iOS firmware by force upgrade of latest firmware signed from Apple server. The Tiny Umbrella allows users to use SHSH blobs from previous firmware to create an IPSW that allows older firmware restoring where Apple is no longer signing it.
Tiny Umbrella Beta currently supports iOS 8.1.3 and 8.2 and other version will be made possible in the future.
Download Tiny Umbrella for iOS 8 here: https://ow.ly/Kn3Tp