I found 5.1 on a russion board.
But here is the link to a download folder that contains 5 dff Fw versions.
You can download the whole folder at once if you like,total download size is 3.46GB.
Or download each individually.
I flashed all of them as a test and only tried them quickly but here's what I found.
5.1.1 stock jxd 101:
Dont bother flashing this really as be default screen stays in portrait mode however I didnt see if it could be rotated cause as I said my device has touch touch screen issues.
511j78003gb101d3gb1600v600:
Seems ok but native key mapper does not work
7800b3gb511:
Seems ok but native key mapper not work
final511j7800gapsroot:
Doesnt boot past boot up
jxd7800511k101overcl1800g600d720d4gb:
Doesnt boot past boot up
So just judging by the names Id guess 7800b3gb511 may be the choice.
Ofcourse feel free to flash all in let me know what you find cause as I said,I didnt spend much time on those that did work anyway
In the end I flashed the kitkat custom rom back on as it has a keymapping feature.
Link here:
https://cloud.mail.ru/public/2wcG/5oaKyDBfk/