while the tmous version is still sitting on 8.1.1 (build 14219).
i figured out a way to get it to latest wp8.1.2 build (15148) the manual way (iutool cab sending).
how to use iutool -> see there
i had to spoof 2 different other devices to obtain those cabs. so it took some time/work.
01 htc w8 tmous 0P6B140 14203-14219.txt (diff updates, also available officially via OTA update)
02 htc w8 tmous 0P6B140 14219-14226.txt (diff updates, preparation to move on to wp8.1.2)
03 htc w8 tmous 0P6B140 14226-15127-15145-15148.txt (diff updates, wp8.1.2)
if your phone is already updated officially via OTA from 14203 (latest wdrt rom os version) to 14219, you can skip step one.
then send the 14219-14226 cabs, let it reboot and install automatically (gears) and let it migrate your data as usual.
then send the 14226-15127-15145-15148 cabs all in one step. let it reboot and install automatically (gears) and let it migrate your data as usual.
now you should be on the latest wp8.1.2 build.
some might prefer this over w10m until htc fixed their apps for w10m (camera crashing when applying effects for example).
hopefully htc will fix them and release a official w10m rom for this beautiful device.
enjoy and leave me a thanks.