*** 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 miro (ST23a)
Firmware version: 11.0.A.5.8_R5D
Region: Latin America (Generic) [1265-8939]
Android version: 4.0.4

Xperia miro_ST23a_11.0.A.5.8_Latin America_Generic 4.0.4
Sony Xperia miro (ST23a) Android 4.0.4 firmware - Generic Latin America