[knc1]

Your installing the wrong KUAL package.

The "Hotfix" is put in the visible, top level, of USB storage and then installed with either UYK or just a reboot.
You need to install a very recent "Hotfix" since earlier ones did not provide the ;log runme and ;log mrpi search bar commands.

There is a "Regular" booklet build and a "Special" booklet build for the installation of KUAL.
Perhaps either coplate or Niluje could say which one you need.
But if you try both, be certain to use any provided un-install after each attempted install. That should minimize the chance of two different *.jar files being present.

Note: the "Special" booklet build is special in the obfuscation Amazon used on the booklet interface.
The failure mode with running the wrong KUAL booklet build is a blank screen and no error message.
If they changed it again with 5.11.1.1, then we need another (different) special of the "Special" build.
Dealing with obfuscated Java is way above my paygrade. Somebody else will have to do that "fix".

Since the KT3 (and I suppose the KT4) are one of the Androdized Kindle models, they are probably among the first to receive special, new, "features" internally.