Unlocked iPhone warranty?

[Ironic Namesake]

I bought an iPhone at the end of last year which has now gone faulty on me - it is an American model which was unlocked when I bought it.

Part of the touch screen has broken - will my warranty be valid when I send it to them?

If not, is there any way I can undo the changes, and get it back to normal?

 

[J1234]

It shouldn't matter that it's American version - Apples warranty is worldwide.

Take it into an Apple Store and they should sort it. Restore it in iTunes, and it should be fine.