Hve you tried to add a font of your own? One that supprts all the characters you need?
Originally Posted by Jinke_Website_Help_Page
7. How to change font library?
A:First you should create a directory "fonts" on SD card root diectory. Copy your font library(*.ttf) to this directory ("SD://fonts").And insert SD card to V3.
Step 1.Enter bookshelf.
Step 2.Press "OK button" and pop-up menu will be shown.
Step 3.Select the "Settings" option,then enter the system settings interface.
Step 4.Press "Number3 button", enter to font replacement interface.
Step 5.according to figures corresponding button to select font. (Make sure the fonts library is suitable)
Step 6.If you do not like your own font library, you can restore system default font library by the same way.
Works with LBook firmware too (tested), and probably most of the others.
You could also try the TripleBoot
firmware. Has a lot of default fonts.