Beware! The Nokia Cyan update for Lumia devices has left a couple of users' phones bricked. This problem is particularly affecting those who were previously running Windows Phone 8.1 Developer Preview with BitLocker encryption. In case you are one of those who have been affected, you will need to download and run the Nokia Recovery Software Tool to "un-brick" your Lumia Smartphone.
"We are currently investigating the issue. We have paused delivery of the update to customers using the Preview for Developers, and will resume once a fix is in place. Customers whose phones have been affected should use the Nokia Software Recovery Tool to return your Lumia to a normal commercial software state before downloading the Lumia Cyan update." - Microsoft