You didn't mention which phone ...
Search 'Lumia (your model #) Service manual' >> @ the end of the Service Manual, there is a key combo which will do a HARD RESET (don't forget to backup your data / pull your SDcard) & take it back to original (factory) status. From there, you can update to whatever version you want.
OR
you can get NSU (Nokia Software Updater), but I believe that'll re-install current version (which is probably what they did @ service.)
OR
^^^ what he said ^^^
Last edited by MDK22; 01-14-2015 at 02:57 PM.
01-14-2015 01:46 PM