You can now use official Nokia Software recovery tool, in case you face issues with software or software updates. If your phone is not responding, it appears to be stuck or is not starting you can try to recover it at home by using this recovery tool.
Two important bits for those of you who want to flash firmwares on their Nokia phones. Nokia’s latest “Nokia Software updater retail 4.1.0” has come with Lumia WP8 “dead-phone recovery mode“. So, in case your phone goes dead or stuck during the process of flashing or while resetting your phone, you can simply plug-in your phone and use the “my device doesn’t boot up” mode to recover your phone.
There is risk however with use of NSU and one can loose warranty if the firmware is still unapproved by country or if anything like power, connection etc go wrong you can brick your phone. So, do it at your own risk :P.
In case if you want to know suitable firmware for your device click here to check the Lumia product code related firmware list.
For downloading the NSU retail 4.1.0, click here.