Make sure to back-up your iPhone's operating systems and functions before committing to this (identical to a "Restore Point" on Windows), just so have a state you can restore your phone in case ...

If you're an iPhone user, you may have experienced your device getting stuck in recovery mode. This can be a frustrating experience, as it can prevent you from using your phone or accessing your data.

Putting your iPod Touch into its Device Firmware Upgrade mode bypasses the currently installed operating system, allowing you to upgrade, restore or downgrade your device's firmware. Software ...