[Anak]

Originally Posted by DNSB

I'm wondering if the different results are caused by the RMSDK renderer (epub) and ACCESS renderer (.kepub.epub) handling hyphenation differently?

Further note: part of the patching I do—and had forgotten about—is to copy the hyphenation dictionaries that were supplied in 3.3.1 to the current firmware when I apply the various patches (Metazoa/GeoffR) created. I'll have to remove them and see what happens.

Probably not, both engines use the same hyphenation dictionaries.

Spoiler:

Yes, you can copy these stock dictionaries manually for previous firmware releases, they are part of RMSDK and in "Adobe format" / Libre Office or Open Office format:
Adobe

UTF-8
LEFTHYPHENMIN 5
RIGHTHYPHENMIN 5
% ADOBE CONFIDENTIAL
% ___________________
%
%  Copyright ©2010 Adobe Systems Incorporated
%  All Rights Reserved.
%
% NOTICE:  All information contained herein is, and remains
% the property of Adobe Systems Incorporated and its suppliers,
% if any.  The intellectual and technical concepts contained
% herein are proprietary to Adobe Systems Incorporated and its
% suppliers and are protected by trade secret or copyright law.
% Dissemination of this information or reproduction of this material
% is strictly forbidden unless prior written permission is obtained
% from Adobe Systems Incorporated.
%
% Version 1.0.1 August 23 2010
%

Open Office / Libre Office

UTF-8
LEFTHYPHENMIN 2
RIGHTHYPHENMIN 3
COMPOUNDLEFTHYPHENMIN 2
COMPOUNDRIGHTHYPHENMIN 3

Hyphenation only works with a dictionary and a link file.
Hyphenation dictionaries are stored in

KoboRoot.tgz\KoboRoot.tar\.\usr\local\Kobo\hyphenDicts\

This location is (now) empty. Hyphenation dictionaries must be installed manually to this location.

Link files, are stored in

\KoboRoot.tgz\KoboRoot.tar\.\usr\share\hyphen\

which links to /usr/local/Kobo/hyphenDicts/, i.e.: /usr/local/Kobo/hyphenDicts/hyph_nl.dic, or /usr/local/Kobo/hyphenDicts/hyph_it.dic
Default link files:
German: de_DE
English: en_US
Spanish: es_ES
French: fr_FR
Italian: it_IT
Dutch: nl_NL (new)
Portugese: pt_PT

The easiest way to install the stock hyphenation dictionaries is to make a copy of previous firmware release.
Open the (copy) firmware file (KoboRoot.tgz) with 7-Zip and delete almost everything in it. You should only keep these locations and files:

\KoboRoot.tgz\KoboRoot.tar\.\usr\share\hyphen\
\KoboRoot.tgz\KoboRoot.tar\.\usr\local\Kobo\hyphenDicts\

And save the modified firmware file.

To install dictionaries for other languages, i.e. Hungarian
Code: hu-HU
Find a Open Office / Libre Office dictionary file (use Google) and add the hyphenation file to

KoboRoot.tgz\KoboRoot.tar\.\usr\local\Kobo\hyphenDicts\

Add the link file (hyph_hu_HU.dic) to

KoboRoot.tgz\KoboRoot.tar\.\usr\share\hyphen\

(the link file contains this line: /usr/local/Kobo/hyphenDicts/hyph_hu.dic), which links to the previous installed Hungarian dictionary file (hyph_hu.dic).

Hyphenation can be made more or less agressive by adjusting the values of

LEFTHYPHENMIN 5
RIGHTHYPHENMIN 5

A higher value is less agressive, a lower value more agressive.
If you use Microsoft Windows to edit these files you might need Notepad++ or a similar editor.
Files must be saved in Unix format EOL and as UT8 w/o BOM.