If you can't wait for a solution, Microsoft does have an idea. The software giant suggests that those with the developer preview, downgrade to commercial software first, before downloading Nokia Cyan. If it's too late and your phone has been bricked after an attempt to install the new OS build, you will need to use the Nokia Recovery Software Tool to "un-brick" your handset.
Keep in mind that it is only those with the Windows Phone 8.1 Preview for Developers using BitLocker, that are having the problem. If you're running Windows Phone 8 on your handset, waiting for Nokia Cyan to arrive just like any ordinary Joe, you shouldn't have a problem at all. This must be the Mobile God's idea of payback against those who were able to use the developer preview of Windows Phone 8.1 to brag about receiving Cortana before the update rolled out to others.