If you have recently encountered a file named Flashtool_0.6.9.1.epub on your system or during a download search, you are likely confused. You are looking at a file typically associated with Sony Xperia smartphone flashing, but it is disguised as an electronic book (ePub) file.
Flashing firmware requires three main components: the Flashtool software, the correct USB drivers , and a firmware file in format. How to flash your device - Sony's Developer Portal Flashtool 0.6.9.1.epubl
Flash custom recovery images (like CWM) and Busybox to prepare for custom ROMs. How to Use Flashtool for Flashing If you have recently encountered a file named Flashtool_0
Older versions of Flashtool handled .sin firmware files differently. For users creating custom .ftf bundles from old stock ROMs, 0.6.9.1 is less strict about file structure than modern releases. How to flash your device - Sony's Developer
You may have seen the filename ending in or similar variations on file-sharing sites. It is important to note that Flashtool is a desktop application , typically distributed as an .exe installer or a .jar file.
Without proper drivers, Flashtool won't detect your device.