[GeoffR]

Originally Posted by Nick_1964

Something is wrong with the value.

Sorry about that, I hadn't updated the address for the 2nd alternative. Here is the fixed patch (I've updated the patch_kobo_3150.zip attachment in post #1 too):

Spoiler:

<Patch>
patch_name = `Set kepub hyphenation`
patch_enable = `no`
#
# The built-in kepub stylesheet has a line "* { -webkit-hyphens: auto; }"
# to turn on hyphenation, but it is only used if the device's justification
# button is set to full justification. With this patch enabled hyphenation
# will always/never be turned on, regardless of justification button setting.
#
# (Note that if the publisher has set the hyphenation in the book's stylesheet
# then that will override the built-in stylesheet.)
#
# Alternative 1: Always turn kepub hyphenation on
replace_bytes = 91FA92, FC F6 7C E5, 01 20 01 20
# Alternative 2: Never turn kepub hyphenation on
#replace_bytes = 91FA92, FC F6 7C E5, 00 20 00 20
</Patch>