Today, Microsoft released the Windows Phone GDR3 Preview for Developers.
Microsoft explicitly stated that once you’ve chosen to install the preview OS, you cannot revert back to the older version, and that your device’s warranty maybe voided.
When you opt in and apply a prerelease update, you can only move forward with updates. When the update is publicly released for your device, you will once again be in a ‘released state.’ There is no path back to a prior release/update.
You guys maybe thinking, “WTF!! I want to try the GDR3 preview now! But I want to have a fallback just in case something wrong happens!”
Well fear no more! The truth of the matter is, YOU CAN ALWAYS REVERT BACK TO GDR2 AMBER!!! 🙂
How? Just do the exact way of ‘manually updating your Nokia Lumia’s firmware via the Nokia Care Suite’
I just did. And I’m back to GDR2 Amber without any issues! 🙂
UPDATE: I can confirm that this process also works in my Lumia Phones updated to the Windows Phone 8.1 developer update released last April 14th, 2014. If you have newer Lumia models, you can download the NokiaSoftwareUpdaterForRetail.exe. Do note, however, that the Nokia Software Updater for Retail, ONLY downloads the firmware specifically intended for your Lumia model. The NSU for Retail can be installed side by side with the NCS 5.0