The bootloader - or - at least one of them, got messed up.
I dont have that device, but, for some hints have a look here

https://docs.google.com/document/d/1...rE/mobilebasic

Its not for the Lunia 925, so there is some work to do

or, here
http://ronhks.hu/2016/02/28/fix-your...-no-vibration/

which have some more