How do I Backup Original Xperia mini Android 2.3 Firmware without Root or Unlocking Bootloader?

[YabuBaker]

How do I Backup the original Xperia mini ST15i Android 2.3 Firmware without Root or Unlocking Bootloader?

I want to upgrade to the official Android 4.0 ICS because of all the new features, however I read that some apps & games crash in ICS, so I want an original 2.3 firmware backup "just in case."

After lots of searching and tons of dead links, I found out that I cannot:

• Use the Sony Update Service (SUS) or PC Companion (PCC) to download the 2.3 version.
• Download the firmware and flash it with FlashTool (2 problems: Requires unlocked bootloader; Xperia mini not supported)

So, is there any official way to do this?

Please remember:

1. I don't wan't to void my warranty by rooting or unlocking the bootloader
2. It's not convenient for me to go to a service centre.

Thanks for your help!

[Rickard]

You can not backup the phones firmware (at least not without root). If you want to go back to Android 2.3 you should contact a local service location that can downgrade the phone for you.