Because I have issues that started after the update to 7.1.1, I want to rollback to 7.0. On Sony Mobile's forums, I was pointed to an article telling how to do this with Flashtool. http://www.xperiablog.net/2016/03/12/install-xperia-marshmallow-using-flashtool-and-xperifirm-guide/ Well, I want to create a backup before I do this. It says I do this by creating a firmware file. I followed the instructions to open XperiFerm Downloader, I chose 2015 devices, Z5, 6653. I know that my phone was made in the UK (Sony Mobile Support tells me this) and I don't see any US options. I see 6 UK options. I don't know which carrier this one was made for (I just know it as unlocked). So I chose Customized. There were 2 options there and I've tried both (R2E and R12C). I downloaded them then closed as instructed. When it goes back to Flashtool, it eventually errors out after trying to create it: ERROR-null. What's wrong and how do I fix it? Please help? I wanna fix my phone.