Press and hold the Power button for about 10 seconds
Master reset Sony Ericsson P990i
Use Master reset to reset your phone
Control panel -> Other -> Mater reset
Important: All user data, as well as pre-installed media files and application data files (including, for example, backgrounds, ringtones and pictures), will be deleted and settings will be set to the state they were after you selected the language. The selected local language will be restored.
If you want to keep installed applications, unmark the Delete user installed applications check box.
Format internal disk Sony Ericsson P990i Symbian hard reset
Switch to P990 service menu
Hold down Space key on QWERTY hard keyboard
Jog Dial Up / Press * + Jog Dial Down / Jog Dial Down / Press * + Jog Dial Down / Press *, then choose format internal disk
If nothing works: As last resort do a Sony Ericsson phone repaire with PC Suite. Use this method to hard reset AFTER INSTALLATION----> TOOLS > PHONE REPAIR
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.
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