UNSOLVED The best support is to keep install instructions actually
I messed around about 3 weeks for installing Ubuntu Touch on my device (Sony F8131).
It should result in the recognition, that the latest firmware was missing on my phone. But why did this happen?
Simply compare the install instructions of F8131 and F5131 (which are quite similar). You see that for F8131 you only have the links to the UBPorts-Installer, while there is much more information for F5131.
That is why I recommend you to keep an eye on the technical instructions for installation on your internetsite, which could save the forum from many unnecessary questions and maybe keep some people from reinstalling Android.