An FTF file is a firmware file used to flash updates on to a Sony Xperia smartphone or tablet using programs such as FlashTool or XperiFirm. It contains ROM firmware that can be flashed on to Sony Xperia devices to update the operating system (OS).

In order to update your Xperia device's OS, you can download and install firmware files to your computer using Xperia Companion (available for Windows and macOS), which replaced the Sony Update Service (SUS). This is the usual process for the average Xperia user. However, if you find a need to share the firmware with another user or need to flash the firmware without downloading it again, the FTF file is very useful. Xperia users can create FTF files by downloading the firmware using Xperia Companion and converting them to the FTF format with the FlashTool or XperiFIrm tools. Users can then share the FTF files with other Xperia users allowing them to update their device's OS with specific firmware.