*** YOU NEED TO REGISTER ON THE FORUM BEFORE YOU CAN ACCESS THE DOWNLOAD LINK ***
INSTALLATION INSTRUCTIONS
http://www.xperiablog.net/2015/03/17/guide-to-installing-xperia-lollipop-using-xperifirm-and-flashtool/
- Open link above and skip to the section entitled “FlashTool steps”.
- As you have already downloaded the FTF firmware file, skip to the section where you need to “Flash device”.
XPERIA FIRMWARE DETAILS
This is official stock Sony Xperia firmware.
Model: Sony Xperia go (ST27i)
Firmware version: 6.2.A.1.100_R4H
Region: UK (Generic) [1265-2276]
Android version: 4.1.2

Xperia go_ST27i_6.2.A.1.100_UK_Generic 4.1.2
Sony Xperia go (ST27i) Android 4.1.2 firmware - Generic UK