Try this:
https://www.mobileread.com/forums/sh...postcount=1795
No Idea if there were some changes in code stucture in newer firmware versions, like there was a change in the way margin values were represented sometimes around firmware 5.5.x (IIRC the values used to be in pt/px, and now are in some decimal/float type numbers that map to some amount of pixel).
I'm not aware of any newer instructions and not sure if there was any feedback from users of newer firmwares. The tools needed are the same, files are probably still the same so it only a matter of the Java code itself.
I think I haven't done those edits since the early days of Paperwhite 1 (maybe the last time I did that type od of edit I was still using Kindle 3/Kindle Keyboard), afterwards I just used the prebuild ones. My old PW1 (now used by my father) is still on firmware 5.4.4.
Since we had to wait quite a long time until the jailbreak for PW3 & firmware 5.5.x or newer firmware was discovered I've gotten used to reading with smallest factory margin... the other main reason for editing those .jar files was re-defining font size value and firmware 5.6.5 had the "FONT_RAMP" thing that enables you to the same thing... so when I finally could jailbreak my PW3 and have gained SSH I was to lazy to do the whole jar edit thing. Custom fonts and personalized font size gradation is good enough for me now. Those two are not optional
