Prepare tools
Mobile phone SD card
G620 ROM card brush pack
Procedure
1) now we put the ROM card brush package downloaded online to the root directory of the SD card on the mobile phone.
2) Now we shut down the phone, and press the volume up key + volume down key + power key to go to recovery.
3) then we use the volume key to move the cursor to [clear data/restore factory settings] and then we select [yes-clear all data]. Then we press the power key to confirm.
4) now let's go back to the recovery main interface, use the volume key to select [Clear Cache Partition], and then click [yes-clear Cache] and press the power supply to confirm.
5) after the operation is complete, we will return to the recovery main interface, and click "install zip refresh" -- "read the refresh history from/sdcard". Then we select the file that we just placed on the SD card, for example, [yes-install XXXXX.zip], press the power button to confirm
6) after the flash is finished, click restart option-> restart the phone now.