Huawei U9200E Training Course page 22

Force update and system recovery
1 Copy the upgrading document to dload file package.
Make sure your handset is power off. Insert the MICRO SD card into the
handset.
Pressing the VOLUME UP key and VOLUME DOWN key, and then press the
POWER key to power on the phone and enter the Software Upgrade
Mode.
2 Enter to Settings->Privacy>Factory data reset->Reset phone->Erase
everything，to reset to factory settings to recovery the operation system.
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