*** 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 Z3 (D6616)
Firmware version: 23.1.C.0.385_R15C
Region: US (T-Mobile) [1286-4514]
Android version: 5.0.2

Xperia Z3_D6616_23.1.C.0.385_US_T-Mobile 5.0.2
Sony Xperia Z3 (D6616) Android 5.0.2 firmware - T-Mobile US