If you hang around Android development long enough, you’ll start running into file types you don’t normally deal with. While some are simply used because of user preference, others are used by OEMs as a sort of proprietary file—such as the SBFs used by Motorola. However at the end of the day, users will eventually have to learn how to deal with these files. One such file type is FTF, and it’s typically used on Sony Xperia devices. Now, users can extract FTF files and turn it into flashable zips.
While it is posted in the Xperia Mini, Mini Pro, Active and Ray forums, the method should be usable on pretty much any Sony Xperia device. Written up by XDA Forum Member Knight47, it requires a few applications—namely, FTF Extractor, 7zip, and some additional files to make it all work. Once everything is downloaded, the method is essentially simple.
In short, you unpack the system files and repack them with the proper files to make everything flashable. Namely, the kinds of files you’ll be adding are root files and the META-INF. After that, flash and be happy. This guide is potentially useful for pretty much anyone who has to deal with FTF files on a regular basis.
For the full tutorial, head to the original thread.