I have an iPhone 3GS that I want to restore to latest supported iOS (currently it's jailbroken on some version of iOS 4.0.1).
How would I go about it, without loosing all data? Can I run a restore from iTunes? Latest version of iTunes (12.2.1) doesn't even recognize that I have a device plugged in.
I don't want to restore another jailbreak version. I want to restore a "proper" iOS