Readers can explore the new features of Windows Phone 8.1 and how to update to it here.
Note: Before proceeding, remember to Backup your personal data.
Preparation: Nokia Lumia device, USB cable, Laptop or PC, and Nokia Software Recovery Tool. You can download the Nokia Software Recovery Tool from here.
To downgrade your device, follow these steps:
1. Install Nokia Software Recovery Tool on your computer and launch the program.
2. Connect your phone to the computer using a USB cable.
Once the Nokia Software Recovery Tool detects your phone, it will display information about the device model and software version.
Simply click on Install to download the software package (approximately 15'). Then, all you need to do is wait for the process to complete.
If you already have the Firmware on your computer, you can copy it to the following path (C:Program Files (x86)NokiaPackagesProducsts)
In this article, I'm using the Nokia Lumia 520 with its Firmware named RM-914
https://Mytour.vn/ha-cap-winphone-8-1-xuong-winphone-8-0-nokia-24n.aspx
After copying, start and connect your phone to the computer as described above, then click install and wait for the restoration process to complete
