So, I sorta thought that I had got this phone to encrypt itself, but it didn't. So I was trying again last night, and it finally did it. But then, after it said 100%, now when it boots, the keyboard app dies and I can't enter my unlock password.
But that's not all of it yet - I can get it to go into fastboot and flash modes, but because I disabled some things in developer mode settings (to secure it) I can't now flash the bastid. When I try to flash it, it just reboots itself and goes back to the encryption unlock screen and tells me the keyboard doesn't work.
So now I have something to 'amuse' myself with over the next day or two. I am not used to these sony devices and they don't give you access to the fastboot or recovery menu, so there is no way to make it do a factory reset, either. And of course, finding good, useful information about it is a nightmare. I suppose xda probably will have a solution somewhere in there, but now I have to find it.
I have thought of the idea of finding someone with a usb keyboard and an otg cable so I can unlock the phone and enable the developer mode shit. Well, we'll see
Update
Fortunately, there was a way to get it to work. The FlashTool just needed to be let to do the setup stuff, with the new/old 4.4 rom selected, it 'prepares' it, and then brings up an instruction screen how to get it to switch to flash mode. Then it reflashes.
To be honest, I miss lollipop, I am going to upgrade it directly this time. Benefits of having it rooted have been dubious at best, and since I reflashed it many apps have been forgetting their configurations, the steemfest app was not showing its data on the display...
CYANOGEN FRICKIN MOD! 13!!1
Well, for a change after much doom and horror, I found there was a cyanogenmod 13 image that supposedly should work with a Sony M2 device. I installed it. It ran. I b0rked it fiddling with trying to get the recovery back to install the Gapps zip. So I reflashed, re-enabled all the dev powers, dug around and found the right boot.img file, flashed it again in fastboot, then after a couple of false starts with the wrong file, I got it working, and this time I scheduled TWRP to flash CM13 and then Gapps. Now, 100% back up and running, it even remembered all my apps and redownloaded, reinstalled (maybe they even have configs as I had them)...
So there will be a post coming soon to show off the pretty CM13. w00t