How would change a hacked iphone running android back to iOS?

There's a hacked iphone 5 running android on ebay. I'm wondering if I bought the phone how would I changed it back to iOS?

Is it even possible to change an iPhone to Android? Its fake.

Thats a fake don't but it

There's no Android on the iPhone 5. There once was a project to install Android on an iPhone 3G, which didn't work any more on the 4 and further models.

There's, however, a Chinese iPhone lookalike copy running Android: the GooPhone i5s. Usually available for 100… 150$ new - and no, you can't install iOS on that one.

Since iPhone uses Apple's hardware and iOS has drivers related to it Android can't be installed on an iPhone. The phone you saw on ebay must be a replica of iPhone called Goophone. It could also be a photoshopped image so beware of it. Spending money on such a product will only end up being a loss.