Microsoft has started rolling out Lumia Cyan Update for windows phone 8.1 but users who had already installed windows phone 8.1 preview for developers are not able to install Cyan Update. So to install Windows Phone 8.1 they need to Downgrade windows phone 8.1 to windows phone 8.
Recently US carrier AT&T announced the rollout of a Lumia Cyan update with new Windows Phone 8.1 for the Nokia Lumia 1520.
But those who are running Windows Phone 8.1 Preview for Developers on the Lumia 1520 did not receive the Lumia Cyan update, whereas those on Windows Phone 8 did install the update.
It then appeared the Lumia devices running Preview for Developers and using BitLocker full disk encryption were having a problem while upgrading to Windows Phone 8.1, which resulted in locking of the phone.
This problem is not limited to only Lumia 1520. Till now Microsoft has released cyan update for 920, 1020, 820 and 720 Lumia phones. Most of the phones who have bitlocker installed, are facing the same issues.
What Microsoft said to these issues after Revealing Cyan Update:
“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.”
Nokia Lumia users who are facing the 8.1 install issue, can update their devices after downgrading to windows phone 8 from windows phone 8.1 preview for developers. Once you are downgraded, you are ready to go to install windows phone 8.1 without any further issues.
Those who wish to Downgrade to windows phone 8 must follow below step by step guide. Before downgrading, you are advised to back up your windows phone data.
To Back up your phone data on windows phone follow these steps: Go to Settings>> Backup>>App+settings>> Back up now.