Huawei U8520 Duplex hard reset

Press and hold VOL UP + CALL + POWER ON U8520

Select wipe data/ Factory reset.

or  Dial on phone screen U8520 reset code: ##258741 then press call key

Restoring U8520 Factory Data
If you reset your phone to the settings that were configured at the factory, all of your personal data stored on the phone,
including information about your Google account, any other accounts, your system and application settings, and any
applications you have downloaded will be erased. Resetting the phone does not erase any system software updates
you’ve downloaded or any files on your microSD card, such as music or photos.
1. On the Settings screen, touch Privacy > Factory data reset.
2. When prompted, touch Reset phone, then touch Erase everything. The phone resets to the original factory
settings, and then restarts.

Preparing for the U8520 Upgrade
1. Download the upgrade file from the appropriate websites.
2. The file you download will be compressed. Use the unzip software on your PC to decompress the upgrade package. The upgrade package has a folder structure — be careful you do not change it. This folder is called dload — do not rename it, either.
3. Use the USB cable to connect your mobile phone to your PC.
4. Copy the folder to the root directory of your microSD card.
5. After you have copied the file to the microSD card, disable the USB mass storage feature.

General advice: Before you buy a new cell phone or new tablet, please try the following procedure to repair your device in a software way. First charge your battery, backup your important data if possible and in most cases take out SIM and SD card before doing factory reset. It is impossible to recover your data after doing a hard reset, so online backup is always important. For all of your data, a backup should be done on an external device, hard drive, raid system or media. With or without insurance, if your cell phone lost, damaged or stolen at least your invaluable data is backed up in a safe place. If you are about to sell your phone and you want to wipe your personal data, or if your phone affected with virus you have to do a hard reset. In some cases, you can delete the forgotten password or lock pattern from your device as well. All information is for devices with stock based ROMs. If you are using rooted device, always back up your EFS folder first, containing your IMEI info, etc.! Please also note, that a hard reset operation will not unlock your mobile phone's SIM lock or network lock, but it will remove the unlock pattern, remove the user password or PIN password (NOT the SIM card's 4 digit PIN code). Also note that the firmware version will not be affected in any way, it will not be downgraded, it will remain the same you are using and if you have rooted your device, root privileges remain also unaffected.