yea it will be gone and you need to find the way to root for stock rom

should be available on XDA.

was the update successful? try to re-update it. plug in (do the same methods)

dont worry, wont waste time redownloading the whole rom since its already stored on ur C drive somewhere..

got tick wipe data? (make sure u backed up)
but you can try not to wipe first and reflash it with SUS software.

SUS = sony update software/service

http://www.sonymobile.com/gb/tools/update-service/

try this and see
its an official software.

no prob..

so problem solved?