[GUIDE] How to downgrade your Nokia Lumia to Windows Phone 8.0 from Windows Phone 8.1 Developer Preview

Microsoft has started rolling out the Windows Phone 8.1 update to various devices. Unfortunately the update was halted for those handsets running the Windows Phone 8.1 Developer Preview, because of a bug that affect a small subset of users. Fortunately the following guide will show you how to downgrade to Windows Phone 8.0 so you can get back to upgrading your device to Windows Phone 8.1.

[NOTE] This guide is only applicable to Nokia Lumia Windows Phone users. You will need a PC running Windows Phone 7 or higher in order to use this method.

Before proceeding, you are advised to backup your device first (Settings > Backup > App + settings > Back up now) before starting the restore process.

1. Download the Nokia Recovery Tool ( US | UK ) and install it on your computer
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2. Open Nokia Software Recovery Tool.
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3. Connect your Lumia to the PC with a USB cable.
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4. You will see which software version you can install on your Lumia – Click install below that.
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5. You will need to acknowledge that the data and content on your phone will be erased. If you can still access your phone, make a backup by going into settings -> backup . You will also need to know that photos, music and apps will be wiped during this reset process. Click that you understand and then click continue.
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6. You will now begin downloading the software. Network speeds vary, but your download might take about 15 minutes.
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7. The software will now begin installing to your phone. Do not use your phone or disconnect the cable during this step. Just go for a quick walk while your phone and PC do their thing.

Once you are back on Windows Phone 8.0, you can then proceed to download the Windows Phone 8.1 and Lumia Cyan update from AT&T. As soon as that is completed, you can hard-reset the phone. The reason for the hard reset is so that the OS can offer up the Restore process from the backup you created earlier. Of course, if you prefer to start completely over, then you do not need to wipe the device.


source - WPCentral