@niem: You must use "booklet" version of KUAL (Update_KUALBooklet_v2.7_install.bin) since with firmware 5.9.2 killed support for "active content" aka "kindlets" (KUAl.azw2 = kindlet).
To install that bin file you'll probably have to use a version of MRPi that gets triggered via searching for ";log". The way newer generation of Kindle devices was doing from the day one.
For more info take a look at spoiler for step #8 in
jailbreak thread
The part that goes like "KOA and KT3 owners". The same applies to KV, PW3 and other devices that have been updated to firmware 5.9.x.
So if you already have latest snapshots version of MRPi you "just" have to copy that "Update_KUALBooklet_v2.7_install.bin" to "mrpackages" folder and run MRpi by "searching" for " ;log mrpi".
It's little backwards: in the past you used to run MRPi from KUAL and now you're running MRPi to initiate installation of KUAL-booklet version
After doing it you have KUAL "book" (I guess? I've never used booklet version of KUAL... my PW3 is safely "paused" on firmware 5.8.11) and use it as always to configure other hacks.