- Take FTF backup using PC Companion and FileSet Decrypt feature of FlashTool
- Unlock the bootloader using FlashTool (Disable driver signing on Win8 before trying this)
- Phone won't start up now. It will remain stuck at the Xperia splash screen
- Use fastboot.exe to do
fastboot.exe flash boot boot.img
from the downloaded CM build. (Any build that is compatible with your phone, extract it and you will see the file. Copy it to the same folder as fastboot.exe and run the command.) - Power on, press VolUp on seeing purple light to go to recovery. (This can be different for different devices)
- If this is working, copy the CM build onto the SD Card
- Again use step 5 to go to recovery, wipe data once and wipe cache twice.
- Choose install zip and select the CM build zip file that you copied into the SD card
- After successful installation of CM zip, select "Reboot system"to see the CM splash screen.
All references to the CM build zip above can be replaced by the zip file of the ROM of your choice. Always ensure that you are using a ROM that is compatible with your phone. Using uncompatible ROMs rarely bricks the phone, but the chance of that happenning is definitely not zero.