Trouble with Korean font when converting ZIP to EPUB

[junj]

I have books downloaded on YES24's reader app which is saved into my computer as 2 folders ("META-INF" and "OEBPS") and a file ("mimetype"). Since it's broken down, I combined them into a ZIP and converted the zip to epub with Calibre, specifying utf-8 character encoding but the resultant book comes out as a bunch of ????, (English, Mandarin and Korean) letters and symbols. I have the Korean language pack installed. Tried looking around for solutions but nothing has been helpful so far.

I have de-DRM plugin installed, but otherwise I've done nothing else to remove the DRM on these books, not sure if that's what's causing these words to be unreadable, or if it's some other issue. I'm a complete beginner with all this stuff and would sincerely appreciate any advice or help with this please

For example, the first page looks like
��v��\އ�.����P��M��]�a����wM�pw����9� d.Ҡ����씓�`�/ix�ޣF��!�(�pق����u[��W�;{�郝��� ^ f���<�ϛ�Ӂ��6�]`*GPG�h)ۭ ͞� n��xο���w�v��-r���n�WA�)��'i=ٓ�1���N���̸Z�D�~.ںO� ��5�)q�~�6�'�>� ���G<��V�Y�c�*q�-�$��rW�mK.��$'|�J�*~��� E�����N4����TEw�#��X����G%�>�SM����2[-���c�e��x�pC�-!i1�$��6�ډR�G��o(���K�^���F����������?p��1�p"$N�r� 8 \q6|�ED$h{ � ���W��R+mX/l���� �i�#w���

META-INF contains:
> container.xml
> rights.xml

OEBPS contains:
> content.opf
> toc.ncx
(folder) Fonts
> KoPubBatangLight.otf
(folder) Images
> cover.jpg
> fioret_.jpg
(folder) Styles
> Stylesheet.css
(folder) Text
> cover.html
> Section00001.html
... till Section00008.html

[DNSB]

Have you specified Korean language in the stylesheet or HTML files? Anywheres? See the Language page in the Daisy Accessible Publishing knowledge base page.

[kovidgoyal]

https://www.mobileread.com/forums/sh...d.php?t=186697