In this tutorial, I show how to backup your EXISTING OFFICIAL LATEST (!) Sony Ericsson Xperia firmware. This can be a GENERIC firmware or a (carrier) BRANDED firmware but must be an OFFICIAL Sony Ericsson firmware ALREADY on your phone.
Again, this will download the LATEST firmware available for your device or SI build. You CANNOT use this method to backup an older firmware.
This process forces Update Service to download the LATEST EXISTING OFFICIAL firmware and to reinstall it on your phone. Once the firmware is downloaded through Update Service, you can copy those files to another folder and subsequently decrypt and extract the files to create a FlashToolFile (.FTF extension) for use with Bin4ry’s FlashTool.
Making a backup allows you to modify your existing firmware, install custom ROMs, or otherwise tweak your Xperia and keep a copy of the official firmware for restoration, if/when needed. e.g. for warranty purposes.
This ONLY works on phones with LOCKED bootloaders. If you’ve unlocked your bootloader, you can NO LONGER use Sony’s apps (Update Service, PC Companion) to update/flash your phone (some phones can re-lock their bootloader.)
It does NOT unlock your bootloader (or relock it).
It does NOT network/SIM unlock your phone (or relock it).
Your phone does NOT have to be rooted.
Flashing via Update Service will WIPE EVERYTHING off your phone. BACKUP FIRST!
e.g. SMS Backup & Restore, Sony Ericsson Backup, Titanium Backup, APN Backup (3G settings), etc.
Existing (official) firmwares:
LT15a arc v2.3.4:
LT18a arc v2.3.4:
Before starting, I recommend installing BOTH Update Service AND PC Companion:
You also need the FlashTool to decrypt and repackage the firmware:
Original developer thread:
Update Service typically downloads the firmware files to the following folder:
64-bit system: C:Program Files (x86)Sony EricssonUpdate Servicedb13740270blob_fs
32-bit system: C:Program FilesSony EricssonUpdate Servicedb13740270blob_fs
If you can’t find the folder, do a search for “13740270”.