Explore this topic: how do you restore aspire 5315 to factory settings? sometimes they have a hidden partition which saves an image of all your original settings
If you don't have installation or recovery media then you'll need to take additional steps to prepare for the day you might need to reset to factory settings.
What Happens If You Restore Factory Settings On Your Phone
How to Reset HTC Droid Incredible 2 - Factory Reset - Tom’s Guide
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