Hello,
A wired keyboard does not work well, but it is very complicated to explain this here. I try...
I use the settings and the players menu, i.e. where new players are added, edited or players removed. So let me add a player.
First problem (maybe not directly related to the keyboard handling?):
The page starts by default with the active focus on the first element, which is "New Online Account". That is ok; however, immediately a black box pops up, but that belongs to Amazon's Fire TV behavior I guess: That box shows numbers and letters and it's a screen-keyboard. If it is possible to hide that when a real keyboard is attached, that would be much better. Then, also another problem would be avoided: If a user does not want to add a "New Online Account" but an "Existing Online Account", no unnecessary screen-keyboard would pop up, which the user first has to close before he can go to the second element "Existing Online Account". In other words: If at all a screen-keyboard is needed (i.e. only if no real hardware keyboard is attached), then it should first pop up after the user has selected the element where keyboard input will be needed. Now, it pops up immediately.
Then there are other problems with that screen-keyboard (maybe you have no influence possibilities on it): E g. when deleting a mistyped letter, that does not show up on the screen-keyboard and also on the text field behind (STK's GUI) the correction does not seem to have effect.
As far as I remember, none of these problems occurred with STK 1.1 on the Fire TV with a wired keyboard. Everything worked quite nicely (well, I needed the keyboard only rarely, i.e. for adding players).
I have not tested a wireless keyboard yet, because I do not have it back yet.