How to Flash And Update Sony Ericsson Xperia ST25I

• Charge your Xperia U to at least 80% so the phone doesn’t run out of power while the flashing is in progress.
• Backup all your data (Apps, Contacts, SMS, Call Logs etc).
• Download Flashtool from here.
• Download the latest 6.1.1.B.1.89 Firmware from here.

NOTE: PakDroid© is not responsible if you damaged your device or did not follow the steps correctly.
Now to start the process:
1. After installing Flashtool, open the following path C:\Flashtool\firmwares and delete all content in that folder.
2. Copy the Firmware (.ftf) file that you downloaded and paste it in the ‘firmwares’ folder.
3. Run Drivers.exe (located in C:\Flashtool\Drivers) and install drivers for Xperia P, U, Sola & Go and also select Flashmode and Fastboot drivers, let them install.
4. Open Flashtool and select the Black Bolt icon and choose ‘Flashmode’
5. After the next window appears select your firmware (i.e Xperia U 6.1.1.B.1.89 ST25i)
6. Make sure all the options that are displayed in the screenshot above are ticked. (NOTE: If you own an Xperia U ST25a then select ‘Exclude Baseband’)
7. Press OK and wait for Flashtool to prepare the firmware for flashing on your Xperia U.
8. Once it is done preparing it will ask you to connect your phone, follow the steps written here:

• Power Off your Xperia U.
• Put it in ‘Flashmode’ by holding the volume down button and connecting the USB Cable until the transparent bar turns green.
• Keep holding the volume down button until the percentage bar starts progressing, after it has reached 5% then let go of the volume button.
• If it gets stuck anywhere just wait 20-30 seconds and it will continue itself.

9. Once the Flashtool Log displays: ‘Flashing Finished’, remove the USB Cable from the phone and let it reboot. It may take up to 5 minutes. After it has rebooted, you may set up your Google Account and once you’re at the homescreen, reboot the phone once more.
10. After it has rebooted the second time, you may normally use your phone.