Thought this is a pretty helpful thread that could help answer a lot of poster questions:
[GUIDE] Complete solution/guide for Unbricking x10 - xda-developers
If you have any questions along the way, don't hesitate in creating a new thread on here and asking for help.
PS. Thank you window7 from xda
[GUIDE] Complete solution/guide for Unbricking x10 - xda-developers
Step 1
Download the latest flash tool.
Flashtool - Xperia devices flashing
Step 2
Unzip the Flashtool to your desktop.
Step 3
Choose and Download the stock rom you wish to flash.
Please download the FTF version.
SIN version is for using Command Prompt (ADB push).
STOCK ROM
Step 4
Place ".ftf" rom file in folder name "firmwares" in the flashtool folder (the folder that unzip at step 2)
Step 5
Run FlashTool.exe
Step 6
Click the Flash button and select the Firmware you downloaded/chosen.
Step 7
It will prompted you to connect your phone in flashmode.
Follow the instruction given to enter into flashmode.
1, Unplug usb cable
2, Turn of your phone.
3, Hold the back button.
4, Plug in the usb cable
5, Wait for it to turn green light
Step 8
Wait till it finished flashing (It will tell you to unplug the usb cable)
Step 9
Now your phone should be stock (unbricked)
Step 10
Buy me a coffee or beer(Just kidding)
FAQ
1, When do I need to do this?
A, When you stuck at boot screen (Sony Ericsson)
B, When you flashed the wrong kernel
C, When you facing serious bootloop
2, Will I lost everything I had on both phone memory and SD card?
YES for phone memory and NO for SD card.
If you have any questions along the way, don't hesitate in creating a new thread on here and asking for help.
PS. Thank you window7 from xda
