Follow the instructions from the links above, read the steps carefully, and be sure you read it completely, do not rush through the text. Then do the steps carefully, rather you read it twice or more often than forgetting something. And always
check your result and if something goes wrong do not panic or shut down your phone
, there are solutions for the errors, that could appear. If there is no solution to your problem, post your error here and someone will help you, but if you carefully follow all steps, there should not happen any problems damaging your phone.
Please notice, you do the steps on your own risk and you will lose warranty.