Just installed 4.3.0.12 on my xperia10 II dual sim and gps works fine.
On installation (indoors) and trying MagicEarth, Puremaps and GPSinfo I was disappointed at first and not any apps got a fix.
The next day outside it took about 30secs to find all the 19 satellites and since then it’s not more than a few seconds for any of the above apps to get a fix.
In my book that’s good enough. 
location settings:
- Location allow
and
- Device-only mode on